Post Acceptance
Guidance
For Distributed Generation
Contents
Introduction
Who is this guide for?
Post Acceptance Connection Process
Information required
Information Provided
Contact
Appendices
1. Introduction
Electricity North West own, operate and maintain the North West’s electricity distribution
network and provide connection services to a range of Distributed Generation (DG)
customers.
As numbers of connections continue to rise we need to find ways to make it easier for our
customers to connect to our network. As part of our commitment to improving the information
available to our customers, we have produced the ‘Post Acceptance Guidance’ to assist you
through the connections process.
If you are looking to accept a Connection Offer from us, we recommend that you read this
guide carefully to make sure you understand all the steps in the process and what you need
to do at each stage.
2. Who is this guide for?
This guide is designed for our Distributed Generation customers, who include:

Domestic customers

Business customers

Generation consultants

MCS accredited installers

Housing Developers

Community Development organisations
This list is not exhaustive and we acknowledge that there will be many more organisations
who may be involved in the connection process of a new DG development.
This guide is designed to complement the bespoke information provided by ENWL following
Acceptance of a Connection Offer. The information provided in this pack covers the process
at a high level for both Low Voltage (LV) and High Voltage (HV) connections.
2
3. Post-Acceptance Connection Process
There are a number of steps detailed below which we are required to complete for your
project before permission to parallel the generation with our network. Please note that whilst
we will do everything we can to ensure that your target energisation date is achieved,
progress will be heavily dependent upon you providing us with relevant and correct data at
key stages and other factors (i.e. legal consents and road closures).
Legal Consents
Post Acceptance
studies
Delivery/
Construction
Pre-energisation
preparation
Testing &
Commissioning
Post Acceptance
studies
Delivery/
Construction
Pre-energisation
preparation
Testing &
Commissioning
Legal Consents
Legal Consents
For many developments legal consents can cause delays if the landowner for your proposed
site has not been approached or consulted on the development. Therefore we recommend
that you start this process as soon as is practically possible. For the majority of developers,
this is following acceptance.
We require land rights to install our equipment on privately owned land. This includes
equipment placed on the development site and may also include equipment placed on
adjacent third party owned land (including land owned by the developer’s landlord). This
applies to Distributed Generation schemes much in the same way as it applies to other new
connection schemes.
Unfortunately we are unable to start programming in the construction phase of your project
until we have all the necessary consents and permissions we need to access and install the
infrastructure for the connection.
For more information on land rights, please see our online guidance and booklet.
3
Post Acceptance Studies
Legal Consents
Post Acceptance
studies
Construction/
Delivery
Pre-energisation
preparation
Testing &
Commissioning
The network may have changed since we first undertook our studies and issued your
Connection Offer, therefore we complete several network studies following your acceptance.
These include:






Voltage management (flicker study)
Fault level
Review your Earthing study in accordance with ESQCR part 2 section 8.1 and ENA S34 /
ENA TS 41-24
Harmonics (G5/4 harmonic study) if applicable
Export Limitation Protection (ELP) if applicable
Protection settings (for HV metered connections)
We carry out these studies using data that you provide, and therefore our progress at this
stage is heavily reliant on how quickly we receive accurate and complete information from
you. See Section 4 for a list of the information you need to provide for us to complete this
stage.
Construction / Delivery
Legal Consents
Post Acceptance
studies
Construction/
Delivery
Pre-energisation
preparation
Testing &
Commissioning
For new supplies, or existing supplies where there is a requirement for an export meter, you
will need to appoint a supplier who will install a meter. In order to install your meter, your
supplier will need a Meter Point Administration Number (MPAN number) from you, which we will
provide.
We will liaise with the Highways Authority (HA) and any landowners affected by the work to
arrange and complete construction on site. Should the work require a road closure, please
note we need to apply to the HA with14 week’s notice in advance of the start date. The start
date can only be determined once all relevant consents are in place.
We will issue our Connection Agreement. The Connection Agreement will include the
generation technical operating requirements. For more information on Connection
Agreements, please see our website.
4
Pre-energisation Preparation
Legal Consents
Post Acceptance
studies
Construction/
Delivery
Pre-energisation
preparation
Testing &
Commissioning
Once you’ve appointed an installer for your meter, you will need to arrange an installation
date for the meter before the energisation of the new supply.
You will also need to sign, date and return the Connection Agreement to us, before
energisation.
Finally, we will agree a date with you to carry out the G59 witness test, if required.
Testing and Commissioning
Legal Consents
Post Acceptance
studies
Construction/
Delivery
Pre-energisation
preparation
Testing &
Commissioning
Once the substation has been energised and the new connection is formalised we will:
for LV metered connections
Where the installation is connected to the LV network, Electricity North West witnessing of
the commissioning tests is not required, except for changeover type connections where the
total generator nameplate capacity exceeds 100kVA. You must submit the full results of your
commissioning tests to Electricity North West for approval.
Upon receipt of satisfactory test results, a ‘Formal Permission to Operate Private Generation
Plant in Parallel with Electricity North West’s Distribution Network’ certificate will be provided.
for HV metered connections
Conduct witness testing for the standard G59/3 commissioning tests and any other
applicable tests (e.g. ELP).
Following a successful G59/3 commissioning procedure we will authorise you to operate the
generation in parallel with our network.
Electricity North West will issue the signed Connection Agreement.
5
4. Information required
To complete the studies in the stage above (Post Acceptance Studies), it is essential that
you provide us with the following information to your generator and installation.
Please see the table below for the information you will need to provide for LV or HV metered
connections.
Metered Connection
Voltage
LV
HV
Single Line Diagram
Yes
Yes
Full generator technical specifications
Yes
Yes
Export Limitation Protection
Yes
Yes
Earthing
Yes
Yes
Transformer details
No
Yes
Protection settings
No
Yes
Rotating Machine information
If applicable
If applicable
Table 1: Information required for LV/ HV metered connections

A Single Line Diagram (SLD)
a) This should show the full generator connectivity up to the exit point
b) Your SLD should clearly indicate ownership boundaries and G59 controlled
Circuit breakers together with synchronising Circuit breakers (CBs)
c) Your SLD should clearly indicate the earthing arrangements for the size of your
generator.
d) Your SLD should include emergency tripping requirements
This will be a working operational drawing and you will need to laminate the final version
for posting in our substation and at appropriate locations on your premises.
G59 protection controlling HV CBs is normally prohibited. Please see the terms and
conditions issued with your acceptance.

Full generator technical specifications
a) Individual generator fault level contribution for a 3 phase short circuit at the
generator terminals:
i) Peak asymmetrical short circuit current at 10ms.
ii) RMS value of the initial symmetrical short circuit current.
iii) RMS value of the symmetrical short circuit current at 100ms.
iv) Rated terminal voltage
b) Rated terminal voltage
c) Rated terminal current
d) Genset (prime mover & generator) net registered capacity (MW)
6

Export Limitation Protection (ELP)
a) This needs to be included on your SLD
b) We will require a methodology statement regarding the protection
c) The protection will need to be witness tested to confirm primary and secondary
injection
To avoid costly modifications we would advise that equipment should not be procured
until the method of Export Limitation Protection has been agreed between Electricity
North West and you.

Earthing
Please provide your earthing study for review in accordance with ESQCR part 2 section
8.1 and ENA S34 / ENA TS 41-24

Transformer details (HV metered connections only)
a) Name plate rating
b) Impedance on rating
c) R+JX on rating

Protection (HV metered connections only)
a) We need details of your private network (SLD) and preferred protection settings.
Rotating machines
If you have a rotating machine, you will need to provide:
a) Apparent power rating MVA (to be used as a base for calculating generator
parameters).
b) Prime mover rating (kW).
c) Active power and reactive power import during start-up (induction only).
d) Generator impedances
If you are using converter/inverter technology, you will need to provide:
a) Full inverter specifications.
b) Harmonic emission currents up to the 50th harmonic for each inverter.
b) Step / Power ramp-up characteristics in MW/min (for flicker analysis).
We only carry out a G5/4 stage 2 predictive voltage assessment if the inverter harmonic
currents necessitate it and /or the HV infrastructure is known to have harmonic voltage
distortion greater than 75% of planning levels. Typically, background measurements are
excluded from routine assessments.
7
5. Information Provided upon Acceptance
Electricity North West will provide the Network Parameters at the Point of Connection
(POC) or Exit Point as appropriate.
6. Contact
If you have any further questions on your DG scheme, please contact your designated
Electricity North West Planning Engineer.
For more information on general standards and testing you can expect as part of your
project, please see the ENA’s guide to DG Connections.
7. Appendices
To assist you we have attached the following documents:



8
SLD Guidance and Examples
MPAN form (customer to complete Section 3)
Template for generator data ‘Gen data request’
Protection settings request form (for HV metered connections only)
Extract G59/3-Dual Supply labelling (DSL) and Operational Diagram
(Single Line diagram, SLD)
DSL The attached examples illustrate the differing ways installations may comply with 11.2.5:
For premises not dedicated to generation, it may not be readily apparent that generation exists. The location
generating plant is likely to be obvious so DSL need not be extensive.
SLD it is a condition of the Connection Agreement with Electricity North West that all generation installations
shall display an accurate SLD located at the exit point and other locations of Generating Plant
IN ALL CASES IT IS THE GENERATORS RESPONSIBILITY TO COMPLY WITH THESE REQUIREMENTS
-1-
MPAN REQUEST FORM
MD Supplies (Normal, Import and Export)
Section 1
From
(for ENWL use only)
Section 2
From
Contact tel
Department
Date
Do you wish the MPANs to be sent to Developer/Customer
Scheme Details
If so give contact details in Section 3 below
Connector Name:
ENWL Planner Name:
ENWL Planner Tel:
Section 3
Customer Details
Project Ref. No:
Customer Name:
Customer Contact:
Customer Tel:
Supplier:
Supply Address
Name/No.
Street
Village/Suburb
Town/City
County
Postcode
Contact Address (if different to Supply Address)
Name/No.
Street
Village/Suburb
Town/City
County
Postcode
Section 4
MPAN Details
Number of
MPANS required
MPAN Request Type
New Supply
Add Load (on existing MPAN)
Service Alteration (on existing MPAN)
MPAN Type
Normal
Multifeeder
Import/CWOG
Export
Export Fuel Type
Intermittent
Non - Intermittent
Please complete the following PROPOSED details for the MPAN(s)
MPAN
Assoc.
MPAN
Site Type
Reading Type
Voltage Type
Supply Voltage
No. of Phases
MPAN
Assoc.
MPAN
Tariff/LLF
Max Imp/Exp Cap (kVA)
Agreed period
Fuse Size (amps)
SIC Code
Assoc. MPAN
Whole Current
CT Class
CT Rating
CT Ratio
VT Class
EXISTING MPAN(s)
Item
MPAN
New MPAN(s)
MPAN Number
To be replaced
by NEW MPAN?
If yes, enter
NEW MPAN item
No.
1
2
MPAN Number
1
2
Add loads and service alterations ONLY
Type of Work
Proposed
Planned Start Date:
New LLFs
NHH
531 Non MD Quarterly
751 NHH LV
752 NHH LVS
961 NHH Export LV
962 NHH Export LVS
Item
HH
801 HH LV
802 HH LVS
803 HH HV
804 HH HVP
HH Export Intermittent
971 HH Export LV
972 HH Export LVS
973 HH Export HV
974 HH Export HVP
E.G.
PV
Wind
Hydro
Engineering Report
Mpan Form - blank
None
CT Change
Fuse Change
Meter Change
HH Export Non-Intermittent
981 HH Export LV NI
982 HH Export LVS NI
983 HH Export HV NI
984 HH Export HVP NI
E.G.
CHP
Diesel
Landfill
G59/3 protection disabled
on all inverters
42x250W PV
panels
52x250W PV
panels
52x250W PV
panels
52x250W PV
panels
10kW fronus
inverter
12kW fronus
inverter
12kW fronus
inverter
12kW fronus
inverter
20A
20A
20A
20A
49.5kW PV
Array
SLD
20A
20A
20A
20A
PV/DB
DSL
DSL
100A
FIT
Meter
90kW CHP
DSL
CHP control panel
with export energy
monitoring
SLD
G59/3 ComAp
mainsPro relay
located in panel B
2nd floor ventilation plant room
100A
DSL
sync
DSL
100A
DSL
DSL
Generation
Marshalling
Panel
200
sync
G59/3 ComAp
mainsPro relay
300A
DSL
DSL
load circuits
315A
located in ground floor
plant room no2
300A
Ground floor electrical room
kW converter
module
SLD
DSL
630A
Exit point= HV cable
box terminals on HV
metering unit
Customer
E/M trip (next to meters)
Ownership boundary
Electricity North West
KEY
Export monitoring CT's
Generator
Remote Metering
Panel
Tripping and
Indication panel
TP&N ACB/MCB/MCCB
automatic device
E/M trip (next to meters)
Meter Room (within 15m of S/S)
TP&N isolator
SLD
Minimum requirements for labelling:
TP&N sw/fuse
DSL to ENW
specification
4p contactor
Dual supply label =
DSL
Single line diagram (SLD) =
G59/3 Device controlled by G59/3 relay
sync
Synchronising CB
sync
Synchronising Contactor
Notes
When the export monitoring CT's detect export in excess of 20kVA, the CHP
control panel will initiate a G59/3 trip via the ComAp Mainspro relay and open
the CHP contactor within 500ms.
G59/3 protection disabled on all inverters or set high to prevent maloperation
The generation tripping and indication facitity shall be provided and maintained
by the generator if it is necessary shed generation under system abnormal.
The functionality shall be in accordance with Electricity North West
specification ES259/EM-trip.
SLD
Illustrative only, these symbols do not need be shown on the
SLD
Single Line Diagram for:
SAMPLE
Drawn By
Approved by
Last amendment
Drawing No:
Date:
1MW PV Array
1MW PV Array
1MW PV Array
1MW PV Array
1000kW
inverter
1000kW
inverter
1000kW
inverter
1000kW
inverter
1MW PV Array
1000kW
inverter
Monitoring
S
G59/3 ComAp
mainsPro relay
site supplies
S
G59/3 ComAp
mainsPro relay
S
G59/3 ComAp
mainsPro relay
S
G59/3 ComAp
mainsPro relay
S
G59/3 ComAp
mainsPro relay
Generation
marshalling panel
T1
1000kVA
11/.4kV
T2
1000kVA
11/.4kV
T3
1000kVA
11/.4kV
T5
1000kVA
11/.4kV
T4
1000kVA
11/.4kV
Exit point= HV cable
box terminals on HV
metering unit
Customer
Ownership boundary
Electricity North West
Gen tripping &
indication panel
Remote Metering
Panel
KEY
Monitoring CT's
E/M trip next to meters
MCCB / VCB
G59/3
S
Device controlled by
G59/3 relay
Meter Room
(within 15m of S/S)
Synchronising CB
TP DC isolator
Single Line Diagram for: EXAMPLE 5MW PV
Notes
G59/3 protection disabled on all inverters or set high to prevent maloperation
The generation tripping and indication facitity shall be provided and maintained by the
generator if it is necessary shed generation under system abnormal. The functionality
shall be in accordance with Electricity North West specification ES259/EM-trip.
SAMPLE
Drawn By
Approved by
Last amendment
Drawing No:
Date:
Gen Data
GENERATOR CHARACTERISTICS: TO BE COMPLETED FOR EACH GENERATOR
Generator Rating kVA:
Component
Reactance's (% on rating OR %100MVA base)
Notation
Direct axis synchronous reactance
Xd
Quad. axis synchronous reactance
Xq
Direct axis transient reactance
X'd
Quad. axis transient reactance
X'q
Direct axis sub-transient reactance
X''d
Quad. axis sub-transient reactance
X''q
Generator zero sequence reactance
Xo
Stator +ve sequence resistance (ohms)
R
% on rating
saturated
% on rating
un-saturated
Direct axis transient time const.
T'd
secs
Direct axis sub-transient time constant.
T''d
secs
Quad axis transient time constant.
T'q
secs
Quad axis sub-transient time const.
T''q
secs
H
MWsec/MVA
Total rotating inertia constant
%100MVA
saturated
%100MVA
un-saturated
Individual generator fault level contribution for a 3 phase short circuit at the generator terminals
Peak asymmetrical short circuit current at 10ms:
Amps
RMS value of the initial symmetrical short circuit current:
Amps
RMS value of the symmetrical short circuit current at 100ms:
Amps
Rated terminal voltage:
Volts
Apparent power rating (to be used as a base for calculating generator
parameters):
MVA
Notes:
Information Required to Calculate the Protection Settings for Equipment to be adopted or
Protected by Electricity North West Limited
Project Title:-
Project No:-
Information Provided by the Independent Connection Provider or customer
1
Make & Type of Metered CB
2
Protection CT ratio(s)
3
Customers MIC (IMPORT)
4
Customers MEC (EXPORT)
5
Details of any customers private HV
protection - (If no HV protection state
'NONE')
Customer preferred settings for private
HV switchgear (if applicable).
6
Not essential, but Electricity North West will
endeavour to accommodate these settings
to provide discrimination with our metering
VCB. If not provided you may need to
revise your settings if grading is
unsatisfactory.
Additional sheets attached? Y/N
7
(If 'none' please go to
section 7)
o/c =
amps
T/M=
o/c>> =
amps
t (s) =
e/f =
amps
T/M=
e/f>> =
Curve =
(SI,VI,EI)
Curve =
(SI,VI,EI)
t (s) =
Nameplate rating of customers
transformer(s)
If no customer HV protection we also require the following additional information:
8
Transformer rated impedance
Z%
9
Does the transformer have transformer
mounted protection (ACB. MCCB etc)
Yes
R
If 'yes' go to
section 11
No
X
If 'NO' complete
sections10-11
10
Details of LV Transformer tails to be
protected by ENW metering VCB
Length, CSA, Cu or AL,
insulation, No / Ø, Ω/km
11
Details of the customers main LV
incoming protection & preferred settings
if available.
inc full specification
PLEASE ENSURE YOU INCLUDE A SINGLE LINE DIAGRAM WITH THE ABOVE INFORMATION
(This should include HV cable types, CSA and length)
Information to be provided by ENW Project Engineer
Supplying Primary Substation
Substation name and number