Brief for BEAP electrical investigators / engineers
The aim of BEAP is to baseline the capacity, condition and compliance (in that respective order) of
Defence base infrastructure.
Scope boundaries –
Electrically, this means the capacity, condition and compliance of:
 incoming power supplies,
 intake substations,
 HV ring mains distribution,
 HV substations including HV substation building and switchgear,
 LV switchgear immediately downstream of substation transformers (only),
 localised generation (LEGS), central emergency power generation (CEPS), and central power
stations (CPS).
It generally does NOT include:
 compliance to Australian Standards for infrastructure owned by a Distributed Network
Service Provider (DNSP)
e.g. compliance to Australian Standards of incoming supplies owned by an electricity
network provider N.B. compliance to MIEE is still assessed!
 A detailed examination of auxiliary LV switchboards at intake substations (the HV
switchboard is the main concern)
 Removing covers from HV switchgear (other than opening LV control panel doors)
 Excavations around buried cables
 Maintenance activities e.g. Oil sampling from power transformers, infrared heat checks on
LV switchboards
 Assessment of LV reticulation i.e. LV cable routes etc. (except if the incoming supply to the
base is at low voltage)
 Assessment of LV switchboards other than the main distribution board immediately
downstream of a substation transformer
 the non-electrical aspects of a LEGS/CEPS/CPS, unless there are obvious non-compliances.
For example, the escape route from a CEPS substation would be risk assessed for its general
suitability, and the fire protection of the generator halls would be assessed from the
electrical perspective of maintaining generation from an adjacent hall during a fire in one
hall, because fire separation is a requirement of MIEE. However, for example, the
mechanical suitability of a fuel line position would generally not be subject to assessment. If
there are obvious non-electrical non-compliances, note that further investigation needs to
take place, but try as much as possible to stick to the budget and avoid doing non-electrical
inspections as part of BEAP.
Regardless of the above scope boundaries, if during investigations, the base personnel happen to
bring to attention a particular problem that is outside the scope of BEAP, it is best to note the
reported problem then include it in the BEAP issues register, even if it is only included as “Assess
aspect …abc… of the CEPS for mechanical/structural suitability because problem …xyz… was noted
by base personnel.”
The most important scope items are the incoming supplies, the intake substations, the ring mains
and generation. These are items necessary to support all base operations. Individual substations
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and individual LV switchboards, while significant within a locale or to a specific facility, are relatively
insignificant to overall base operations and therefore relatively minor to BEAP.
BEAP is a risk assessment. It is not a compliance audit. Therefore, only the essential requirements
for maintaining a reliable electricity supply and maintaining the safety of personnel and electricians
is assessed. Future power demands are not considered. The essential aspect of BEAP is to assess
the capacity, condition and compliance of the HV electrical network and report on its ability to
maintain, safely and reliably, the existing level of base operations.
Reporting guidelines–
Justification: So that the BEAP reports are reliable, Defence requires that all evidence be
documented in a written form. If anecdotal evidence is all that is available, the anecdotal
information needs to be confirmed by an email.
Condition vs. compliance: For the report analysis, endeavour to put blinkers on, and see condition
issues separately to compliance issues. If they overlap, endeavour to analyse what the root cause of
each particular problem is, evaluating whether it is a non-compliance that causes unacceptable
condition or vice versa. Primarily report the issue in the section allocated for the root cause. Crossreference the issue in the other section as necessary.
Analysis structure: If major issues are encountered with any particular infrastructure component,
the easiest report structure to use seems to be first to explain:
1. what exactly is installed, then
2. the observed flaws / evidence for poor condition / non-compliances, then
3. analyse the causes, and lastly
4. clearly state the risk to Defence and recommend remedial actions.
To approach it in any other order has not worked before.
Capacity Terms:
 Utilisation = how much capacity is used divided by how much capacity physically exists in
the component (e.g. 30A drawn from a transformer rated for 100A is 30% utilised)
 Spare capacity = opposite to utilisation = how much capacity is not used, compared to how
much physically exists (e.g. 30% utilisation is equivalent to 70% spare capacity)
Through the analysis section of each BEAP report, the capacity needs to be discussed in terms of
utilisation rather than spare capacity. Only at the summary sentence in the ‘Assessment Outcomes’
section does spare capacity generally have its first mention.
Criteria: Refer to the start of the report template (Part 3 - Electrical, Tables 2 to 4) for the relevant
assessment criteria. A copy is included in this document for reference.
Drawings –
BEAP is expected to produce a site single line diagram (SLD), a set of colour-coded SLDs and a set of
colour-coded GIS maps. Remote sites do not require a site SLD unless there is HV at the site.

Site SLD - The following items need to be recorded on the BEAP single line diagram:
o

Xxx
SLDs – One copy of each of:
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
o
Site SLD (no colour), drawing number
BEAP-<3-letter site abbreviation>-ELEC-001-<capital letter of revision>
e.g. BEAP-OAK-ELEC-001-B
o
Capacity, colour-coded, drawing number BEAP-<xxx>-ELEC-002-<x>
o
Condition, colour-coded, drawing number BEAP-<xxx>-ELEC-003-<x>
o
Compliance, colour-coded, drawing number BEAP-<xxx>-ELEC-004-<x>
Colour-coded GIS maps –
o
Overview – The following items generally need to be depicted:

Incoming supply cables (these are only required if they are in GFIS or if
owned by Defence, otherwise consider a note to say they are not shown)

ISS locations

CEPS locations

LEG locations

HV substation & switching station locations

HV cable routes, colour-coded for each individual ring mains

Main LV switchboard locations (only for remote sites without any HV)

Do NOT show: (unless the site has no HV distribution)

Main LV switchboards

LV cable routes
o
Main site: Overview, Condition
o
Remote sites: Overview, Capacity, Condition, Compliance
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Capacity, condition and compliance criteria:
Table 2 Engineering Service Assessment parameters
Criteria Used for Infrastructure Sub-Service Assessments
Capacity
Condition
Compliance1,2
Exceeded
A percentage of service capacity
has been used or exceeded as
listed in Table .
Unserviceable
Not capable of functioning as
intended, obsolete equipment /
components, unable to be
maintained – requiring full
replacement / upgrade.
Non-compliant (AS and MIEE)
Design does not comply with
applicable mandatory design
guidelines, Australian Standards
and additional Defence Policy
requirements.
Marginal
A band of service capacity has
been used as listed in Table .
Likely to be non-compliant with
requirements for spare capacity.
Poor
Deterioration is severe and is
limiting the serviceability of the
asset. Maintenance cost would be
high.
Non-compliant (AS) and
Compliant (MIEE)
Design does not comply with
applicable mandatory design
guidelines and/or Australian
Standards, but complies with
additional Defence Policy
requirements.
Fair
Deterioration is obvious and there
is some serviceability loss.
Compliant (AS) and
Non-compliant (MIEE)
Design complies with applicable
mandatory design guidelines and/or
Australian Standards, but does not
comply with additional Defence
Policy requirements.
Good
Signs of deterioration evident,
serviceability would be impaired
very slightly.
Compliant3
Design complies with applicable
mandatory design guidelines,
Australian Standards and/or
Defence Policy requirements.
Within Limits
A percentage of service capacity
has been used as listed in Table .
As new
No visible sign of deterioration,
recently constructed / installed or
recently rehabilitated back to new
condition.
Notes:
1. Non-compliance to Defence Policy requirements is assessed as non-compliance only to those requirements which
are additional to the minimum standard of the Australian Standards or other mandatory guidelines.
2. Additional Defence Policy requirements can include physical and/or capacity requirements.
3. Compliance to the standards and Defence policies is an overall assessment that there are no obvious and
significant deviations from the principles, which are in the standard, and which are required for maintaining the
safety of the installation.
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Capacity is assessed according to various bands of sub-service capacity as detailed in Table 3.
Table 3 Capacity Assessment Criteria by Sub-Service
Sub-Service
Assessment parameter
Incoming
supplies
Max. site demand compared to
authorised demand
<80%
80%<x<100%
≥100%
HV switchboards
Max. current compared to
busbar rating
<85%
85%<x<95%
≥95%
HV network
cables
Steady-state load compared to
cable protection setting or cable capacity
<80%
80%<x<95%
≥95%
HV substations
Max. current compared to
transformer rating
Oil transformers
Oil transformers
Oil transformers
<85%
85%<x<100%
≥100%
Dry transformers
Dry transformers
Dry transformers
<75%
75%<x<90%
≥90%
<85%
85%<x<95%
≥95%
Peak load (kVA)
of supported services
compared to prime capacity
<90%
90%<x<110%
≥110%4
Average load (kVA)
of supported services
compared to prime capacity
<70%
70%<x<80%
≥80%5
Peak load (kW)
of supported services
compared to prime capacity
<90%
90%<x<110%
≥110%4
Average load (kW)
of supported services
compared to prime capacity
<70%
70%<x<80%
≥80%5
Peak load (kVA) compared
to prime kVA rating
< 80%
80%<x<100%
≥100%
Avge load (kVA) compared
to prime kVA rating
< 60%
60%<x<70%
≥70%
Peak load (kW) compared
to prime kW rating
< 80%
80%<x<100%
≥100%
Avge load (kW) compared
to prime kW rating
< 60%
60%<x<70%
≥70%
LV switchboards
Max. current compared to
busbar rating
Alternator
Engine
2Prime-Rated
CPS
Generator Set
Engine
Alternator
CEPS1
Within Limits
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Marginal
Exceeded
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Engine
Alternator
Assessment parameter
Generator Set
3Continuous-Rated
Sub-Service
Continuous load (kVA) compared
to continuous rating
Continuous load (kW) compared
to continuous rating
Within Limits
Marginal
Exceeded
< 80%
80%<x<100%
≥100%
< 80%
80%<x<100%
≥100%
Notes for Table 3:
1. All limits for a prime-rated CEPS must be satisfied, including peak load and average load, for both alternator and
engine.
2. All limits for a prime-rated CPS must be satisfied, including peak load and average load, for both alternator and
engine.
3. All limits for a continuous-rated CPS must be satisfied, for both alternator and engine.
4. Peak capacity for prime-rated CEPS is exceeded at 110 per cent, because short-term overload is permitted in
accordance with ISO 3046-1 (2002) for one in 12 hours and/or not to exceed an annual limit.
5. Average capacity for prime-rated CEPS is deemed exceeded at 80 per cent, to ensure that the required Spinning
Reserve is maintained and because standard service intervals are based on a 70 per cent average utilisation as
outlined in ISO 8528 (2005).
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Condition is assessed for HV substations and LV switchboards according to the application of criteria
detailed in Table 4.
Table 4 Condition - practical assessment criteria
Condition
Category
Condition
Unserviceable
Serviceability
Item cannot provide
power to its rated
capacity
Condition Poor
Condition Fair
Condition Good
Item can provide
power
Item can provide
power
Item can provide
power
Immediate works to
address dangerous
levels of oil
conductivity, acidity
or dissolved gases
are required
Remedial works or
monitoring is
recommended.
No remedial works
for oil conductivity,
acidity or dissolved
gases are
recommended.
Oil leaks
Major oil leaks
Minor oil weeps
No oil weeps/leaks
Functional cable
rings
HV cable ring not
connected due to
poor condition of
substation
HV cable ring
connected
HV cable ring
connected
Floor hazards
Floor tread plates
missing from cable
trenches
Floor tread plates
cover all holes/fit
over trenches
Water in cable
trench
Cable trench
contains water
Cable trench dry at
inspection
Warning labels
(quantity is
irrelevant to
condition)
Warning labels
illegible
Warning labels new
or faded
Maintenance
(oil-sampling)
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Condition
Category
Condition
Unserviceable
Condition Fair
Condition Good
Structure - Doors
Doors
insecure/cannot be
opened
Doors securely held
and able to be
opened/closed
easily
Structure Equipotential
bonding
(quantity is
irrelevant to
condition)
Existing earth straps
have pulled out of
doors
Existing earth straps
are attached
securely
Structure –
emergency lights
Emergency lights do
not work (one or
more)
Emergency lights all
work
Footings appear
badly cracked or
crumbling
Footings do not
appear badly
cracked or
crumbling
Meters unreliable
Meters reliable
Substation
footings
Condition Poor
Footings are
unstable
(Kiosk
substations only)
LV power meters
(LV switchboards
only)
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Section 01 – Description
This section is generally written last. It forms an executive summary.
What to report:
1.1 Overview –



What is the high level overview of the base’s electricity network?
E.g.:
o How many sources of supply? What voltage?
o How many intake substations?
o What does the HV distribution look like?
E.g. Four ring mains with thirty substations (11/0.415kV) distributed around base,
with power factor correction included at each substation
o What generation capacity supports the network? E.g. CEPS
o What generation capacity supports individual loads? E.g. LEGs
Follow with a detailed description of the network.
o Where and how are the supplies connected into the base?
o How old are the connection points?
o How many other customers are connected to the DNSP’s feeders to the base?
o What redundancy is there in the physical arrangement of the incoming supplies i.e.
in the DNSP’s network?
o Power factor correction – is it installed? Does it work?
o Describe the HV cable network topology – What risks to Defence are inherent in the
HV network configuration? E.g. Can a single point of failure result in a long power
outage?
o What backup options are provided? What risks are presented by the lack of backup
or the time taken to obtain backup power?
o If relevant, include: “Airfield lighting completes the electrical infrastructure at
<RAAF Base XXX>. As it is outside the scope of the HV infrastructure investigation,
it is not discussed further.”.
Detached properties:
o Include a general description for each property
E.g. Where is it? What is the land area? Who uses it? For what purpose?
o How are the detached properties supplied with power?
E.g. DNSP-owned pole transformer outside property with LV feed to site
o What redundancy exists in their power supplies? E.g. LEGs
o Are there inherent risks to Defence? E.g. No LEG for a RADAR site?
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Section 2.0 Incoming Supply
Some terms:





Electricity supplier/distributor = DNSP = Distributed Network Service Provider = the
electricity supplier who owns the distribution network / power lines
e.g. Ergon; Energex; Power and Water Corporation (PWC); Western Power etc.
Electricity retailer = the company which bills Defence for the electricity usage = sometimes
different to the energy supplier or sometimes the same company
e.g. Energy Australia; Origin Energy; Synergy; Alinta; Perth Energy; ERM Power
Contestable site = a site which purchases power from an agency other than the local energy
distributor
Authorised demand (Ergon term) = the maximum amount of power permitted through the
connection point. The authorised demand is the network capacity reserved exclusively for
the base. It is defined by the base’s connection agreement / electricity supply contract.
(Other DNSPs should have a similar term in their contracts.)
Contracted Maximum Demand (CMD) (Perth Energy term) = equivalent to Ergon’s
authorised demand
Data required:












Physical arrangement of feeders
Physical capacity of feeders (DNSP-owned)
Physical capacity of feeders (Defence-owned)
– cable installation conditions for derating and cable construction for capacity
Total peak demand on feeders
Demand of other customers
Demand of Defence base
Minimum historical power factor of base
Historical harmonic content of base
Condition reports or visual inspection (Defence-owned feeders)
Is it a contestable site?
GFIS (cable route records)
Connection agreement (authorised demand and guarantee of backup power)
What to report:
2.1 Description –



What is the physical arrangement of each incoming supply? Include cable types and size if
available.
(E.g. sourced from DNSP’s zone substation ABC, leaves zone substation by buried cable of
construction X and capacity X, transitions onto overhead lines of construction Y and capacity
Y, overhead feeder route is through industrial area xyz, total route is x km to the base,
where it transitions onto Defence-owned underground cable of construction Z and capacity
Z to enter the intake substation.)
How many customers are supplied by each DNSP feeder to the base?
What is the redevelopment history of the supplies to the base? (optional)
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

Is there power factor correction within the Defence network?
The following template sentence may be useful: “Power factor correction units, intended to
optimise the sizing of the electrical infrastructure, reduce the current drawn through the
connection points and improve the site power factor, is … e.g. due to be installed by <date> /
currently installed at <location> / etc.”
Include a summary diagram of the incoming supplies, especially if it is a complicated
arrangement.
2.2 Capacity –




Analyse capacity of each incomer, by owner.
What is the utilisation of each DNSP network feeder?
o What is the existing installed capacity of each DNSP-owned incomer to the base?
N.B. DNSPs sometimes set upstream protection settings above the physical capacity
rating of their distribution cables! It is best to find out both the upstream protection
settings and the rated physical capacity.
If this is the case, include the risk to Defence.
There is an example in Oakey’s report, par. 60, “… the cable has a potential
vulnerability to small overcurrents (e.g. caused by high impedance faults), which
could overload the feeder with resultant cable failure.”
o What is the existing historical peak demand on each DNSP feeder from all
customers?
o Hence, what is the utilisation (opposite to spare capacity) in the DNSP network?
What is the spare capacity in each Defence-owned incoming feeder?
o What is the existing installed capacity?
 Include assumptions for cable derating and capacity if necessary. (See
example Table 8 in Oakey’s report.)
o What is the existing peak demand of the base?
 Include its derivation in report
o Hence, what is the spare capacity in the Defence incomers?
What is the risk to Defence from the amount of spare capacity:
o on the main feeder?
 Is there guaranteed spare capacity reserved for the base or is supply of load
growth dependent on the discretion of the DNSP?
 If the spare capacity is limited, what is the limiting factor? Consider
discussing by how much the spare capacity could increase if the existing
limiting factor were eliminated? How major would the works be?
Expensive? Difficult? Should Defence be considering doing this?
o on the backup feeder?
 E.g. Is its installed capacity less than the base’s demand? During a blackout
on the DNSP’s main feeder, will Defence risk losing all operations, some
operations, essential operations, etc.? Is the risk reduced because LEGS will
support essential loads? Is there a CEPS to reduce the risk? Is the risk
unmitigated because the CEPS is inadequate / unreliable?
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Example incomer capacity assumption table
Table 8
Defence-owned Incomer Cable Ratings (Example from Oakey’s Table 8)
Item
ISS1 Incomer
ISS2 Incomer
Cable Number
(DSR 3.14)
E02
E03
Cable Description
Ergon point-of connection 1
Ergon point of connection 2
To ISS1 (Building A103)
To ISS2 (Building C52)
Voltage Rating
Assumed 6.35/11 kV
(Unknown if cable rating is 19/33 kV,
suitable for future 33 kV)
6.35/11 kV
Cable Type
(DSR 3.14)
400 mm2 Copper, XLPE/ High Density
Polyethylene (HDPE), 1 x 3-core
240 mm2 Aluminium, XLPE, 1 x 3-core
Length
(DSR 3.14)
500 m
270 m
Installation conditions
Descends pole, then buried direct in
bedding material, except in conduit for
road crossings.
Limiting factor is installation in conduit.
Conduit depth: 1,650 mm
(1,000 mm to top conduit then 200 mm
between conduit edges thereafter).
No. of cables per conduit: assumed
single.
Total number of HV power circuits in
trench: 3 (cables E02, E41 and E59).
(DSR 3.14)
Descends pole, then buried direct, but
assumed to cross roads in conduit. (DSR
3.14)
Datasheet for XLPE/HDPE cable is
unavailable, so estimate is based on
XLPE-insulated, PVC-sheathed cable
and XLPE/HDPE triplex cable.
Derating factor of 0.81 for potentially 4
circuits (1 future) under road or 0.85 for 3
existing circuits.
Additional derating factor of 0.96 for
depth of lay.
Total derating 0.78 or 0.82.
Estimate is based on XLPE-insulated,
PVC-sheathed cable.
Estimated Capacity
In the order of 400 to 440 Amps,
Based on Olex’s HV catalogue
(DSR 3.62)
284 Amps,
Based on Olex’s HV catalogue
(DSR 3.62)
Site Maximum
Demand
4.70 MVA (247 A)
4.70 MVA (247 A)
Estimated Utilisation
Full site load operated through either
ISS1 incomer or ISS2 incomer.
i.e. 62% utilised
Full site load operated through either
ISS1 incomer or ISS2 incomer.
i.e. 87% utilised
Remarks
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Assumed depth of lay: 1,000 mm.
Assumed no. of parallel circuits: 1 roadlighting circuit
Derating factor of 0.91 for 2 circuits.
Additional derating factor of 0.99 for
depth of lay.
Total derating 0.90.
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2.3 Condition –





DNSP-owned assets are NOT assessed for condition.
o If applicable, include: “The incoming power supplies, upstream of the points of
connection, are owned and maintained by DNSP, <name>, and as such were not
assessed for condition.”
Defence-owned incomers ARE assessed for condition.
Overhead lines: If no other information is available, make an assessment on a visual check
for damage, deterioration, termite infestation and issues with vermin.
Underground cables: If a cable cannot be regarded “As New”,
o When was it last redeveloped?
o Can it be assumed that it was in good condition when laid?
o Can it be assumed that nothing has disturbed it since installation?
o Is its expected life at least, say another 20 years, provided it remains within capacity
limits?
o Cable markers – are these in suitable condition?
o If so, then it can be assessed as good condition.
Are any (condition) risks to Defence obvious?
2.4 Compliance –




For DNSP-owned assets, compliance is assessed against:
o MIEE 2011
o National Electricity Rules
For Defence-owned assets, compliance is additionally assessed against:
o Australian Standards.
MIEE 2011 –
o Physical arrangement - Does MIEE require at least two incoming feeders to this
establishment? Is the arrangement compliant? If not, what is the risk to Defence?
 Risks to Defence –
 Are multiple supplies independent to some degree? E.g. do they
have different routes from the zone substation to the base.
 What availability does the backup feeder have? Is the backup
feeder available all the time? Is it available only by switching? How
long would it take to come online? Is its availability guaranteed, or
subject to the DNSP’s sole discretion to provide backup power by
load-shedding other customers?
o MIEE capacity – MIEE 2011 requires generally that incoming feeders are sized for
the ultimate base load – Each feeder is individually compliant or non-compliant - Can
it be assumed that the capacity of the second feeder has been approved by DEEP, if
its capacity is less than the ultimate base load?
o Contestable sites – MIEE requires that contestable sites comply with the National
Electricity Code.
National Electricity Code –
o Harmonic content
 Are the harmonics generated by the site acceptable to the DNSP?
 For info only: In Perth, the compliance limit is 8% total harmonic distortion
(THD); Western Power’s planning limit is 6.5%.
o Power factor
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o



What is the risk to Defence of non-compliance? Higher costs, energy losses,
disconnection from DNSP network, etc.
Aust. Standards –
o Physical installation (depth of lay and clearances from other services) 1. If it is reasonable to assume that buried cables have remained undisturbed since
installation, then it can be assumed that they remain compliant with Aust. Standards
in respect to their physical installation.
2. If overhead lines are identical to DNSP lines, they can likely be assumed
compliant.
o Cable route records – AS 2067 s4.2.9.1(a) requires that underground cable routes
are ‘appropriately identified’ – hence, the GFIS route is compliant or non-compliant.
If non-compliant, what is the risk to Defence?
Neither MIEE / NEC / AS –
o Reliability of supply - Is there a negotiated connection agreement? Does it stipulate
an authorised demand? If not, is there another method by which a minimum
amount of power is guaranteed to be available for the base?
 Note: The absence of a connection agreement does not mean it is noncompliant. What it does mean is that in the issues register, negotiations
should be recommended in order to guarantee a minimum level of power
supply, to secure exclusive access to spare capacity in the DNSP feeder if the
base is entitled to it, to avoid risking power outages, and to guarantee a
particular level of emergency / backup power.
Do any other risks arise from the physical arrangement or compliance of the feeders?
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Section 3.0 – Intake and Primary Switching Stations


This section includes primary distribution, which is essentially all HV
switchboards and ISS buildings.
Exclusions - Other than a CEPS HV switchboard and its auxiliary power
supply (trip/close batteries), everything associated with a CEPS is excluded from this section.
The CEPS and its associated components are covered within the CEPS section. E.g. CEPS
building, control room, generator control system, batteries for genset starting system,
adequacy of fuel supply, load-shedding system etc.
Data required:










General installation details (sketch of floor plan, checklist, photos =
generally sufficient)
Site SLD
Switchboard maximum demand
o
Metering data for 12 months, if available, OR
o
Site demand AND
o
Logged switchboard currents
Switchboard capacity
o
HV switchboard nameplate, AND
o
Busbar rating, AND
o
HV circuit-breaker ratings, AND
o
Protection CT ratios (if possible)
Overcurrent protection relay models/types, for each tier
Protection relay test records
Oil dissolved gas analysis (DGA) test records, for oil-filled switchgear
Checklist and photos
(Note: A photo of each compartment of each tier can be a lifesaver later, depending on
what issues are found.)
HV switchboard drawings
(Note: Required only if capacity is unavailable from nameplates, or if there are
particular condition/compliance issues with switchboard.)
Auxiliary equipment details, if there are particular condition/compliance
issues
What to report:
3.1 Description –
Note: the level of required detail in the Description section will differ, depending on whether
there are any major condition issues or non-compliances needing later analysis.

What are the salient features of the intake substations and HV
switchboards? E.g.
o
At what voltage is incoming supply?
o
At what voltage are outgoing feeds?
o
How many HV switchboards are in the ISS / CEPS?
o
How are they configured? Bus-ties? Number of feeders?
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o
o

o
o
o
How is auxiliary power provided? (E.g. 240V UPS? 48V Batteries?)
(optional)
What provision has been made for future expansion? On the switchboard?
Space in the building? (optional)
How are the different HV switchboards connected together?
Ring mains?
Interconnectors?
How many distribution substations?
3.2 Capacity –

o


o
o



o

What is the utilisation on each HV switchboard?
What is the maximum demand on the switchboard (usually site demand)?
Explain / justify the maximum demand used
 Has recorded current for a consecutive period of at least 12
months as per MIEE 2011 preference been used?
 If not, what was used instead?
(E.g. a combination of temporary load logging and DNSPprovided annual maximum demand figures.)
What clarifications for temporary load-logging are necessary?
E.g. how was it done? How reliable are the results? Do the results need
adjusting for the season of the year? Were any loads missed? If so, are
the missed loads significant? Were the currents logged simultaneously?
If not, what adjustment needs to be made to the maximum demand?
Include a graph of the logged currents. See example below.
In order of preference, baseline the site maximum demand against:
1. Busbar rating, or if unavailable then
2. Incomer circuit-breaker rating, or if unavailable then
3. Incomer protection CT size.
What is the limiting factor on utilisation?
If the busbar size is significantly different to the other ratings, include
clarification. An example from Oakey’s report par. 162-165 follows:
… The busbar rating of the HV switchboard at ISS2 is 1,250 A, from the
switchboard ‘As Constructed’ drawings (DSR 3.50). The switchboard utilisation,
on first appearances, is therefore considered to be 20 per cent. … It should be
noted that the capacity of each switchboard feeder is limited according to each
individual panel’s circuit-breaker size, the protection CT ratio installed in the panel,
and the protection setting. Each circuit-breaker, including the incomer, is rated for
630 A. On every panel, the protection settings are currently 70 per cent of each
primary CT ratio, which confirms the switchboard baseline is within limits to meet
current demands. ... It is noted that, should the load increase to approach their
ratings, the protection and metering CTs could be replaced with equipment rated
up to the size of the circuit-breakers.… [Based on the busbar capacity, but] noting
that the CTs and circuit-breakers are rated less than the busbar capacity, the
capacity baseline of ISS2’s HV switchboard is considered to be within limits to
meet current demands with 80 per cent capacity remaining.

 Is there a significant risk to Defence?
E.g. Is 99% of the CT protection rating currently being utilised?
What is the risk to Defence? Are any utilisations (busbar, incomer or CT’s)
marginal or exceeded?
o
E.g. (from Oakey report par. 168)
If the ultimate base load of 350 A (DSR 3.43) is ever reached, ISS2’s switchboard capacity
will technically remain within limits with 28 per cent of the busbar rating used. However, as
the switchboard will be operating at 88 per cent of the incomer’s CT rating, it would be
prudent to consider replacing the CTs if the projected loads are revised higher.
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3.3 Condition –




Use the inspection checklist and a keen eye. What condition issues are
there with the:
o
ISS buildings?
o
HV switchboards?
Note:
o
The level of detail required depends on the final assessment outcome.
o
Maintain a keen eye because not every possible condition issue has been
captured in the checklist (such as, self-powered relays being used in a HV
switchboard more suited to externally-powered relays).
What risks are presented to Defence?
o
E.g. Is the condition issue likely to cause failure of the component? Will the
ISS become unserviceable? How high is the risk?
o
E.g. Water in cable trenches: will degrade insulation, decrease service life,
rust cable supports in the trench
o
Etc.
The key is to articulate both the outcome of the inspection, and discuss in
detail the risk/issue supporting the final assessment.
3.4 Compliance –

Compliance is assessed against:
AS/NZS 3000:2007 (including Amendments 1 and 2);
AS 2067-2008 (including Amendment 1); and
MIEE 2011
Include the following paragraph:
<Name which intake substations and CEPS HV switchboards> were inspected by an electrical
engineer and detailed checklists (DSR 3.xx) were evaluated for compliance to Australian
Standards and the MIEE. Inspections of the HV switchboards were facilitated by a qualified
electrician from the CMSC.
What are the major compliance issues against Australian Standards? (Use
the checklist.)
What are the major compliance issues against MIEE? (Use the checklist.)
The following 2 template paragraphs may be useful:
o
“The highest risks are associated with …abc… . Although these issues are
more than likely caused by condition factors, they are also non-compliant to
Australian Standards as AS 2067 section …pq… requires that ‘…xyz…’.”
o
“All the identified non-compliances are listed in the Issues Register (refer to
Appendix A). Key non-compliances to Australian Standards are: …abc… . Key
non-compliances to MIEE are: …xyz… .”
What is the risk to Defence presented by the non-compliances?
o
o
o





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REQUIRED logged current graph:
Figure 1 HV ring currents logged at ISS1 (Example from Oakey Figure 1)
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Section 4.0 – Ring Mains


This section includes all the HV interconnectors and ring mains cables.
HV cable labels are included in this section, not in substations.
Data required:



o
o

Site SLD
Site maximum demand (for interconnector)
Individual ring mains maximum demand
Metering data for 12 months, if available, or
Logged switchboard currents
Protection reports (assessed cable capacities and required protection
settings)





o
o

o
o
Protection relay test records (actual overcurrent protection settings)
Cable schedules
Installation details (derating)
Cable route drawings / GFIS (parallel cable routes → cable derating)
Photos
Cable types
Cable labels
Cable capacity
Cable datasheets, if available, or
Industrial cable catalogues otherwise (capacity tables)
What to report:
4.1 Description –

o

o

o
o
o

Overview of the HV cable network topology
e.g. ring names, how many spurs, types of loads on each ring, how many
substation loads in total, are loads connected to the interconnector, etc.
How is load transferred between HV switchboards?
Via ring mains or via interconnector?
Overview of history / how much is known about the cables
Sizes/types are known or uncertain?
How old?
Routes are well understood or vague? Estimate a percentage accuracy of
GFIS.
If necessary, what documents were used in lieu of a cable schedule?
4.2 Capacity –

Potholing - If relevant, include this template paragraph for potholing:
Physical cable capacity is affected by cable size and insulation type, and installation
conditions (e.g. buried direct/installed in conduit, depth of burial and number of cables
grouped together). The cable installation conditions for <site name> are understood to vary
across the site, but remain generally unknown, without an ‘As Constructed’ cable schedule or
updated GFIS. Potholing to determine installation conditions was not carried out, as there
would have been limited benefit of potholing only a sample of locations.


Estimate physical cable capacities (see example summary table from
Oakey’s Table 17)
o
Are there existing estimates of cable capacities? Are they reliable?
 Note: Some previous base HV reports have not included any derating, nor
given any reason for ignoring derating. Also, especially when site
documentation is wrong, previous reports have used erroneous cable
types, and therefore their capacities are invalid. Therefore, it may not
be wise to reuse previously reported capacities without giving them a
(thorough) sanity check first.
o
What are the installation conditions?
 Explain assumptions (assumed installation conditions and therefore
derating)
o
What are the cable sizes and insulation types?
 Explain method and assumptions
e.g. cable sizes were noted from cable labels; labels either end were
analysed for consistency and compared to the visible cable insulation
types, to any available cable documentation and to network drawings.
 Note: doing a comparison of cable labels OFTEN finds inconsistent labels
either end of the same cable, wrong records, errors on cable schedules
and sometimes labels different to the visible insulation type, even 2 or 3
different cable labels on the same end of a cable or even cables installed
side-by-side which are obviously different physical sizes but are labelled
as the same. All these problems = add to the issues register =
advise/discuss the risk to Defence.
 Note: A cable label different to the visible cable type is not always useless;
it could mean that the cable run has been almost totally replaced but the
new cable was joined outside the substation to a tail of the old cable, to
avoid re-terminating. In this case, the apparently incorrect cable label is
a clue to a joint outside the substation.
o
Hence, what is the estimated capacity?
 Based on what?
E.g. from industrial catalogues, based on the above assumptions for
installation conditions and cable sizes and types

What is the level of risk to Defence, or possible negative outcomes, from
any assumptions, generalities or unknown cable sizes/types.
o
Example risk paragraph from Oakey’s report par. 242:
The risk presented to Defence from unknown cable types is not only that the
current carrying capacity of those cables is unknown, leaving them potentially
unprotected from overload, but also that engineering analysis of the HV network
cannot be completed without assuming a cable type, which affects the reliability
of any HV protection study, fault level study, load flow analysis, etc. This in turn
impacts upon the ability of the network operators to understand the network, to
optimise the current flow in the network and hence minimise power losses, and to
ensure that the equipment is adequately protected from overload or damage.
Subsequently there are potential risks to personnel safety and to Defence of
shortened cable life or should equipment fail, of extended power outages. The
cables presenting the highest risks in this regard are mentioned specifically in this
analysis, but nevertheless the size and type of each unknown cable are
recommended to be confirmed.
What is each cable’s utilisation?
o
o
o
o
o
o
Note that both protection setting and installed cable capacity need to be
checked!
Why is the protection setting preferred?
 Assuming that voltage drop is the limiting factor on cable capacity, the
installed capacity is misleadingly high.
 Presumably a protection study was done before the settings were installed.
Presumably the protection study recommended a setting appropriate to
limit voltage drop.
 Presumably the protection setting has been installed at the permitted
current-carrying capacity, rather than on a different methodology, such
as being much less than current-carrying capacity but just above the
maximum demand or just high enough to discriminate with downstream
protection settings.
Why is the installed cable capacity also needing to be checked?
 In case the protection setting happens to be higher than the installed
capacity.
 In case the protection study was based on erroneous cable data/ratings
(don’t laugh – this has been found to be the case previously!).
 In case the protection setting was installed just higher than maximum
demand or ultimate base load (but this would be very hard to prove
without the original protection study report).
Discuss ‘marginal’ and ‘exceeded’ results by exception.
What are the risks to Defence?
 How certain are the assessed cable capacities? Is it known on what basis
was the protection level set?
 Installed cable capacity, with or without appropriate derating?
 Permitted current-carrying capacity, accounting for voltage
drop?
 Ultimate base load?
 Maximum demand?
 Erroneous cable data?
E.g. from Oakey’s par. 272:
The assessed cable capacities are sensitive to the assumptions made, so it is
recommended that these are validated as recommended in Appendix A.
 Are any cables overloaded or of marginal spare capacity? How likely are
they to fail? E.g. from Oakey’s par 247:
If it is not replaced, depending on how far the cable is overloaded in the future, the
cable could fail or its lifespan could be shortened due to overheating.

Overall assessment: If ANY ring mains or interconnector is assessed as
marginal or exceeded, so must be the overall assessment. The overall assessment is NOT an
average of the cable capacity assessments.
4.3 Condition –

Include this template clarification for only having done visual inspections:
Visual inspections were carried out to assess the condition of the cables. Potholing and any inspection
which would have required de-energisation of portions of the electrical network and interruptions to site
operations were not undertaken.

What is the basis of the condition assessment?
o
o
o
o

Age and insulation type? E.g. Paper-lead = fair, while XLPE = good?
Documented condition assessment provided by the CMSC?
Other?
If based on cable age and type, the following template paragraph might be
of use: (based on Oakey par. 257)
Provided the visual inspection did not indicate any condition issues to the contrary, cable condition
was assessed based on age and type. The paper-lead cables at <site name> are estimated to have
been installed from approximately <start year>, when the site began, until the early 1990’s when
XLPE cables became widely used. Paper-lead cables on the site are therefore approximately 20 to
<how many> years old and were assessed as being in fair condition. XLPE cables, being estimated
at less than 20 years old, were assessed as being in good condition. The following exceptions were
made:
a.
Cables replaced in the <xxx HV upgrade> were assessed to be as new.
b.
Where segments of paper-lead cables have multiple joints in them due to repairs, the
condition was downgraded to poor, due to potential damage as a result of previous faults and
stress.
c.
Segments containing few joins between cables of different type/age were assessed overall
as the lowest constituent condition. For example, a segment containing an XLPE cable jointed to
paper-lead cable was assessed overall as fair.
Include the required condition summary table. (see example below - Oakey’s
report Table 20)

o
o
Assessment Outcome = weighted average.
Overall rating can be the same as, or different to, the worst cable
condition.
Include the risk to Defence
 E.g. of risk from Oakey par. 259 (b) Two long paper-lead sections [are] assessed
as [in] poor condition in the Airfield Ring, [because they] have multiple joints in
them from previous repairs. Joints in cables are one of the common failure points.
However, the paper-lead cables themselves present a low risk of failure. These
are assessed as a low risk to site operations as they are in a ring configuration
and paper-lead cables are common in older networks.
4.4 Compliance –

o
o
o

Compliance is assessed against:
AS/NZS 3000:2007 (including Amendments 1 and 2);
AS 2067-2008 (including Amendment 1); and
MIEE 2011
If data was limited, the following introduction may be useful: (Oakey’s par.
268)
To assess cable compliance to Australian Standards, the primary information required is physical
installation conditions, cable capacities and respective protection settings, and cable records. To
assess compliance to MIEE, the minimum necessary information regards cable capacities (including
fault withstand levels), cable labelling, and cable type.

Include a statement about how the analysis was able to be done on the
limited available information.
o
E.g. from Oakey par. 269
Potholing of the cables was not undertaken as there would have been limited benefit from
potholing a sample of locations across the site. The installation conditions and cable types and
thus the cable compliance have been estimated from the available data which was:
a. Cable type and labelling at substations, by visual inspection (DSR 3.xx);
b. <list other available documentation> (DSR 3.xx); and
c. GFIS cable route records (DSR 8.xx).
Analysis of this data is consolidated in DSR 3.xx. Some cable types remain unknown, either
because cable types were not visible or conflicts between the available data could not be
resolved. Site inspections of the cable labels were facilitated by a qualified electrician from the
CMSC.
AS – What are the non-compliances to Australian Standards?

o
AS compIiance: Installation conditions
Is enough known about the installation conditions to assess them?
 If not, include the following statement:
Compliance to Australian Standard requirements for minimum depth of burial and
mechanical protection of buried HV cables etc. was not assessed.


o
o
o
o
Follow that statement by reporting what is known about installation
conditions
AS compliance: Protection
AS 2067 section 7.2 requires protection from ‘the effects of faults and unacceptable
overloads’.
What capacity and protection data is available to use? Is it reliable? Is it based on
assumptions?
 Reference the assumptions already made about cable capacity, if necessary.
Are the cables protected?
 Include a table of compliance per ring main. See the example from Oakey
Table 22.
 Include a list of which cables in the ring mains are unprotected. See the
example from Oakey Table 23.
What is the risk to Defence? What remedial actions are required?
 Is the assessment valid? Was the data reliable? Do assumptions cast doubt
on the outcome? Does data need verifying? Does a protection study need
revising? Do protection settings need review?
 What is the risk to Defence? E.g. from Oakey par. 273
The risk from unprotected cables is that a severe overload would cause immediate
cable failure, leading to extended power outages and expensive repair, while
prolonged slight overloads would stress the cable insulation and shorten the cable life.

o
o
AS compliance: Record of underground cable routes
AS 2067 s4.2.9.1(a) requires ‘appropriate means of identifying cable routes’
for cables installed underground.
Markers on-site, in situ - This could be assessed in a number of ways.

Explain chosen method.

Compliant or non-compliant?

Previous PMCA comment: When spot checks are used as a sample to make
an overall assessment, the validity of the locations chosen must be
demonstrated. I.e. How were the locations chosen?
E.g. from Oakey par. 274, Spot checks were undertaken in four geographicallydiverse locations, selected across old and new cables, as a sample to assess
compliance generally. Findings from the spot checks are: …
o

Survey data
Estimate how accurate GFIS is.
 Compare GFIS to any available survey data (usually BEAP
commissions a survey of HV pit locations).
 CMSC electricians usually know if GFIS is reliable.
E.g. from Oakey par. 276, Professional surveyors were engaged to verify cable pit
locations. GFIS was updated with the survey data (DSR 8.xx). It showed
<…describe the results…>.


Compliant or non-compliant?
 Cables missing from GFIS = non-compliant
 Badly inaccurate route records = non-compliant
 Etc.
AS compliance: Overall summary – compliant or non-compliant?
MIEE – What are the major compliance issues against MIEE?

MIEE compliance: Ring configuration
Include template sentence, if relevant: (from Oakey’s par. 277)
o
MIEE (section 26.4.2) requires that distribution substations on a ring main system shall
generally be connected to two primary nodes (i.e. <node names, for example, ISS and
CEPS>), although MIEE also provides that Defence will consider approving deviations from
this requirement based on an assessment of the importance or remoteness of the loads.
o
o
o
Is the distribution between 2 primary nodes? Are there HV cable spurs?
Has MIEE approval been given? Can it be assumed as given? On what evidence?
Compliant or non-compliant?
Note: If approval for spurs is assumed to have been granted, then assess
network as compliant.

MIEE compliance: Minimum capacity and insulation type
Include template sentence: (from Oakey’s par. 278)
o
MIEE compliance requires that cables be sized generally for a minimum fault level of 250
MVA for one second and for a minimum capacity of 4 MVA when all derating factors are
applied.
o




Fault level (min. 250MVA for one second)
Are cable fault withstand values available from datasheets?
If datasheets are unavailable, what assumptions can be made?
E.g. light- or heavy-duty fault rating for cable screen?
If datasheets are unavailable, what are the industry catalogue fault
withstand levels for light-duty and heavy-duty screens?
Are either of the catalogue screen ratings compliant to MIEE?
If neither → non-compliant to MIEE;
If one is → there’s a possibility of MIEE compliance. (E.g. Oakey par. 279)
Cable datasheets containing fault withstand levels for the existing cables were
unavailable. Hence, the ability of the network cables to withstand the MIEE fault
level could not be verified. Based on industry catalogues (DSR 3.xx), a heavyduty or high level of fault screen rating would have to have been adopted for the
cables to comply with MIEE in this respect. Without actual datasheets, it is
unknown what ratings are installed.
 What is the risk?
- Can Australian Standards compliance be proven? (E.g. Oakey par. 279)
As the highest fault level within the site (xx kA – DSR 3.xx) is less than typical
light-duty screen ratings, the ability of the cables to withstand a prospective fault is
considered compliant to Australian Standards, even though it cannot be verified
for MIEE compliance.
- If AS compliance is ok → then risk is negligible, provided compliance is
maintained (E.g. Oakey par. 279)
Whilst the prospective fault level on the site remains in the order of xx kA, the risk
to Defence of not complying with the MIEE fault rating is negligible. However,
should the prospective fault level increase over time, beyond the fault withstand
level of the existing cables, there is a risk of cable failure under fault conditions.
Under this future circumstance, the replacement of cables with those of higher
fault ratings would require consideration.
- If AS compliance is unproven → what’s the risk? Do the cables need
replacing? Does fault-limiting equipment need installing? Do protection
settings need review?
Capacity (min. 4 MVA)
o


o
MIEE compliance: Spare capacity
Include template sentence:
MIEE compliance requires that 60 per cent of the cable capacity is not exceeded.
o
xxx

MIEE compliance:
Example cable capacity table:
Table 17
Ring
Ring mains cable capacities
Installed cable types1
150 mm2
Support
(Example from Oakey’s report Table 17)
Cu
Assumed derating / Assumed
installation conditions
XLPE
310 A
150 mm2 Cu
PLYSWA
235 A
120 mm2 Cu
XLPE
150 mm2 Cu
XLPE (3x1c)
276 A
In conduit, Buried at 0.8 m,
No derating for grouping
Unknown size/types between
Substation 11 – 12,
Substation 12 – 23,
Substation 23 – ISS2
310 A
120
Al
Triplex
(assumed XLPE,
based on date of installation)
262 A
(or 157 A)2
150 mm2 Cu
In conduit, Buried at 0.8 m,
No derating for grouping
(or Buried direct, 3 grouped cables
spaced at 0.3 m, depth of 1.75 m
i.e. 0.81 & 0.94 derating factors on
280 A)
235 A
(or 213 A)3
150 mm2 Cu
120 mm
2
Cu
PLYSWA
Lowest
Capacity of
the Ring
235 A
150 mm2 Cu
PLYSWA
Unknown
Buried direct in ground at 0.8 m,
No derating for grouping
(or In conduit, Buried at 1.25 m,
4 grouped cables spaced at 0.2 m
i.e.0.95 & 0.76 derating factors on
218 A)
mm2
Domestic
Estimated
Capacity
XLPE
310 A
PLYSWA
215 A
155 A
70 mm2 Cu
PLYSWA
TBC4
mm2
70, 95 or 120
Cu
PLYSWA
(cables with contradictory
labelling)
240 mm2 Al
Technical
XLPE
155, 185, or
215 A
316 A
Unknown size/types between
Substation 1 – Possible joint en
route to Substation 2
Unknown
150 mm2 Cu
XLPE
310 A
70 mm2
Al
PLYSWA
120 A
Al
Triplex XLPE
185
mm2
150 mm2 Cu
PLYSWA
In conduit, Buried at 0.8 m,
No derating for grouping
275 A
235 A
Unknown size/types between
Substation 20 – 17
Substation 05 – Joint 03
Unknown
150 mm2 Cu
XLPE
310 A
mm2
Al
XLPE
316 A
Cu
PLYSWA
185
mm2
Al
XLPE
120
mm2
Cu
PLYSWA
240
50 mm2
Airfield
In conduit, Buried at 0.8 m,
No derating for grouping
Unknown size/types between
ISS2 – Joint 7
In conduit, Buried at 0.8 m,
No derating for grouping
125 A
272 A
215 A
Unknown
120 A
70 mm2 Al
PLYSWA
125 A
50 mm2 Cu
PLYSWA
Notes for Table 17:
1. Cables are 1 x 3-core, unless noted otherwise. The limiting cable capacity is shown in bold.
2. As this cable has a low capacity and it is also an exit cable from ISS1, approximate derating has been estimated
based on ‘For Construction’ upgrade drawings.
3. As this cable is rated close to the protection setting, approximate derating has been estimated based on ‘For
Construction’ upgrade drawings.
4. Contradictory cable labels put the cable capacity in doubt.
REQUIRED cable utilisation table:
(N.B. 1. Add a column for physical capacity of each cable if it is not included in a cable capacity
table.
2. Change Note 2 as necessary, or if need be, include two columns for Estimated Utilisation (to
show a difference between the ‘installed cable capacity’ utilisation and the ‘protection setting’
utilisation if that is needed at your site).)
Table 18
Estimate of loading on HV cable rings (Example from Oakey’s report Table 18)
Max. Ring Current1
Estimated Utilisation2
Capacity Assessment
Support
77 A
33%
Within limits
Domestic
83 A
54%
Within limits
Technical
124 A
103%
Exceeded
Airfield
18 A
14%
Within limits
Ring
Note:
1. DSR 3.56 – Logged Current Demands, increased by 20 per cent for summer loading.
2. Maximum ring current compared to installed cable capacity.
REQUIRED condition summary table:
(A ‘segment’ is taken to be a whole cable run between 2 substns. It is not between 2 joints per se.)
Table 20
Condition summary - HV rings and Interconnector (Example from Oakey’s report Table 20)
Condition
Support Ring
Segment Qty.
Domestic
Ring
Technical
Ring
Segment Qty.
Segment Qty.
Segment
Qty.
Interconnector
Segment
Qty.
Airfield Ring
Total
As New
4
0
3
1
N/A
8
30%
Good
1
2
2
1
N/A
6
22%
Fair
1
4
2
1
N/A
8
30%
Poor
0
0
0
2
N/A
2
7%
Unknown
(Unable to
assess)
2
0
0
1
N/A
3
11%
Total No.
Segments
8
6
7
6
N/A
27
100%
Fair1,2
Fair3
Fair4
Poor5
N/A6
Fair Overall
Overall
Rating
Notes for Table 20:
1. Reason for unknown cable condition………
2. Reason for unknown cable condition………
3. Reason that a partially unknown cable can be assessed as fair………..
4. Reason that a partially unknown cable can be assessed as fair………..
5. Reason for unknown cable condition………
6. No interconnector cable is installed at <site name> currently.
REQUIRED compliance table – cable protection
(adjust table as necessary to suit available data)
Table 22
Protection settings for HV ring mains (Example from Oakey’s Table 22)
Assessed Cable
Capacity
Ring
Support
Proposed Setting
from GHD
Protection Report1
235 A
(120 mm2 XLPE)
155 A
210 A
(70 mm2 Cu PLYSWA)
(120 mm2
PLYSWA)
TBC4
ISS2 Protection
Setting2,3,5
0.7 of CT
secondary current,
275 A
(150 mm2 Cu
PLYSWA)
Domestic
ISS1
Protection
Setting
equivalent to
280 A
0.7 of CT
secondary current,
equivalent to
210 A
Protected?
No
No
Unknown6
Technical
235 A
120 A
(70 mm2 Al PLYSWA)
(150 mm2
PLYSWA)
125 A
125 A
Airfield
(50
mm2
Cu PLYSWA)
(50
mm2
PLYSWA)
0.7 of CT
secondary current,
equivalent to
210 A
0.7 of CT
secondary current,
equivalent to
140 A
No
Yes (ISS1)
No (ISS2)
Notes for Table 22:
1. DSR 3.43 – GHD Protection Philosophy and Grading Scheme October 2010.
2. DSR 3.54 – Site Investigation Photos.
3. DSR 3.48 – ISS2 Protection Relay Service Report.
4. DSR 3.65 – Cable Analysis Spreadsheet – Contradictory cable labels put the cable capacity in doubt.
5. Note inconsistent ring mains labelling on the switchboard. The ring mains descriptions nominated in the above table
are consistent to the substation numbers labelled on the ISS2 switchboard, rather than the ring mains labelling.
6. The protection settings for the cable ring mains would have been set at ISS1 during the HV upgrade Stage 1, but the
actual settings are unavailable to date. Presumably the GHD proposed settings have been used.
REQUIRED compliance table - unprotected cables:
(adjust table as necessary to suit available data)
Table 1
Ring
Unprotected ring mains cables (AS non-compliant) (Example from Oakey’s Table 23)
Installed cable types
Segment
Assessed Cable
Capacity
Highest
Protection
Setting
Joint 15 – Joint 14
150 mm2 Cu PLYSWA
Support1
Unknown size/type
120 mm2 Al Triplex
(assumed XLPE)
70, 95 or 120 mm2 Cu
PLYSWA
Domestic2
(cables with contradictory
labelling)
70 mm2 Al
PLYSWA
Technical3
Unknown size/type
Between two potential
joins in Substation 03 –
Substation 22 route (In
doubt, could be XLPE)
Substation 11 – 12,
Substation 12 – 23,
Substation 23 – ISS2
ISS1 – Joint 16
Substation 02 – 14,
235 A
280 A (ISS2)
Unknown
262 A
(or 157 A TBC)5
Substation 14 - 13
155, 185, or 215
A6
Substation 08 - 04
120 A
Substation 20 – 17
Unknown
210 A (ISS1 &
ISS2)
235 A (ISS1)
Joint 18 – Joint 08,
Joint 09 – Substation
15,
Airfield4
50 mm2 Cu PLYSWA
Substation 15 – Joint
12,
125 A
140 A (ISS2)
Joint 12 – Joint 13,
Joint 13 – Substation
16
Notes for Table 23:
1. In the Support Ring, note that 120 mm2 Cu XLPE has an assessed rating of 176 A. As the protection setting is only
slightly higher, 180 A, this is considered protected because the Australian Standards ratings are necessarily
conservative.
2. In the Domestic Ring, an unknown cable type between Substation 1 and a possible joint en route to Substation 2 is
considered protected, because it is expected to be either 120 mm 2 or 150 mm2 copper, so compliant regardless of
whether it is PLYSWA or XLPE.
3. In the Technical Ring, an unknown cable type between Substation 5 and Joint 3 is expected to be 150 mm2 copper,
but either PLYSWA or XLPE. It is therefore assessed as protected.
4. In the Airfield Ring, the indeterminate cable type between ISS2 and Joint 7 is either 120 mm 2 Cu XLPE or 150 mm2
Cu XLPE, so is assessed as protected.
5. As this cable has a low capacity and it is also an exit cable from ISS1, approximate derating for cable grouping and
depth of burial has been estimated based on ‘For Construction’ upgrade drawings.
6. Contradictory cable labels put the cable capacity in doubt.
Section 5.0 – Substations
Substations includes all substations components except the main LV distribution board itself.
‘Substations’ includes the HV and the LV switchrooms if they are indoors, whether or not the LV
switchroom is attached to the HV switchroom. This delineation was used in the past so that whether
the main LV distribution boards are included or excluded from BEAP scope, the substation building is
assessed as a whole unit in the substation section.

HV cable labels are included in the HV ring mains section, not in
substations.
Section 6.0 – LV Switchboards
The LV switchboards section includes only the main distribution board. The room in which it is
housed is included in the substation section, not here at LV switchboards.




Metering – what was available? Are the meters known to be unreliable? Are there risks
because the data is instantaneous not historical?
Metering – are the meters ‘intelligent’? why / why not is metering data available from a
comms network (DESN or PCMS)? At a very high level, what works would be required to
implement ‘intelligent metering’ connected to a network so that it can be successfully
remotely monitored?
LV cabling, labelling, tidiness etc.
How adequate is the ‘form’ of construction (compartmented construction)?
Section 7.0 – LEGS



Obtain information from the maintenance mechanic/diesel fitter and/or maintenance
electrician as to the reliability and condition of the generators. (Confirm anecdotal
information by email / record of conversation.)
Be on the lookout for concerns about unreliable starting, overloading, unavailability of
spares etc.
Collect enough information to fill out details of the following table
Copy Harman & Oakey

Section 8.0 – CEPS
Section 9.0 - CPS