Live Replacement of 400kv Busbar Insulators in Brasov Substation
Live Replacement of 400kv
Busbar Insulators in Brasov
Substation
Dr. Ing. Stelian Alexandru Gal- CN Transelectrica SA- Romania
Ing. Marius Nicolae Oltean- SC Smart SA- Romania
Ing. Ioan Sevastre- SC Smart SA- Romania
Ing. Lucian Brabete- SC Smart SA- Romania
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
General wiew
The replacement of 400kV insulator strings was the first
investement project realized in LW technology in a substation in
Romania.
The work was performed in bare hand method, using an
aluminum lather. It was the proper technology for replacement of
porcelain insulators with composite insulators.
The work was performed by a crew from Smart Company- Sibiu
Branch, and it lasted for four months.
May, 2011
Sept,
2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Starting inputs : Brasov Substation
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
For the 400kV busbar, the connection to the devices is made of ACSR
twin conductors, as follows:
- Busbars- system 1 and 2, 2x970/228 mm2 ACSR
- Transfer couple - 2x450/75 mm2 ACSR
- Transversal couple and the connections to the devices 2x450/75
mm2 ACSR
The substation is placed in:
- Meteorological zone: II,
- pollution zone: II;
- From the wind action point of view: zone B;
- From the snow action point of view: zone B;
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Caracteristicile lanţurilor de izolatoare
There are 6 types of insulator strings:
- simple suspension string 400kV, 12 pieces
- double suspension string 400kV, mounted in ”V”, 3 pieces
- double suspension string 400 kV, mounted in „V”, equipped with yoke99 pieces.
- double suspension string 400 kV, mounted in „V”, without yoke- 81
pieces.
- double suspension string 400 kV, mounted in ”parallel”, with yoke- 9
pieces.
- double suspension string 400 kV, mounted in „parallel”, without yoke15 pieces.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Busbar insulation in 400kV Brasov substation
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
LW method justification
By analyzing power readigs on each breezeway (night gap, morning
peak, day gap, evening peak) for two calendar days (working dayWendesday, resting day- Sunday) of each month (January-August 2005)
on each 400kV bay, from Brasov substation, we had the following
observations:
- The transmission of active power usually works from the 400kV OHL
Sibiu and Bradu to the 400kV OHL Gutinas and Darste
- The transmission of reactive power usually works from the 400kV OHL
Gutinas to Brasov to the other 400kV OHL Sibiu, Bradu and Dârste
- One 250MVA 400/110kV transformer provides the power demand for
110kV consumers in Brasov substation, so any transformer (150MW)
can be deenergised
- The simultaneous deenergising of more 400kV OHL may influence the
system’s stability and should be approved by the National Dispatch
Center (NDC).
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Conclusions on the deenergising of the equipment
The replacement of suspension strings in Brasov substation may be
done with deenergised equipment for the following works:
- For the busbar system 2 – 15 Double Parallel Strings and 54 Double V
string may be replaced
- The consecutive deenergizing of T1 and T2 transformers (51 Double V
Strings in total).
Other works which will imply the deenergising of equipments are not
possible to perform; the National Dispatch does not allow simultaneous
withdrawal from service of more equipments
The remaining works should only be done in LW technology
(68% of the work volume).
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Nr.
Criterii de comparatie
Executia lucrarilor cu retragerea
Executia lucrarilor
crt.
( apreciere )
din exploatare a instalatiei
cu tehnologia LST
1
Durata totala de executie a lucrarilor
81 zile lucratoare a 8 ore
135 zile lucratoare a 8 ore cu 1
din care :
cu 2 echipe a cate 4 electricieni
echipa LST ( 9 electricieni )+ 2 zile
- fara retragerea din exploatare
6 zile
135 zile
- cu retragerea din exploatare a unor
instalatii
56 zile
2 zile
- cu retragerea totala a statiei
19 zile
-
2
Costul lucrarilor ( fara TVA )
1.461.201,00 RON
1.412.649,00 RON
3
Conditionarea executiei lucrarilor de
Aprobarea DEN pentru retragerea
Obtinerea mai facila a
obtinerea aprobarilor DEN pentru
din exploatare a unor instalatii
aprobarii DEN pentru executia lucrarilor
retragerea din exploatare a unor
se va obtine foarte dificil sau pentru
instalatii de 400 kV
unele chiar nu se va da
Conditionarea executiei lucrarilor de
Conditii meteo mai permisive
Conditii meteo mult mai restrictive
- inlocuirea lanturilor de izolatoare
Numai inlocuirea lanturilor de izolatoare
4
conditiile meteo
5
Tipul lucrarilor care se pot executa
- inlocuirea cordoanelor de legatura la
aparataje si a clemelor de derivatie
- alte lucrari
6
Continuitatea in alimentarea
Sunt necesare numeroase manevre de
Se poate asigura continuitatea in
consumatorilor
retragere din exploatare a unor
alimentarea consumatorilor
instalatii care afecteaza continuitatea
in alimentarea consumatorilor
7
Pierderi de energie ( putere ) in
Pierderi suplimentare datorita
Cele existente in schema normala
retelele de 400 si 110 kV
abaterilor de la schema normala
de functionare
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Executed Works
- only the insulated strings were replaced, (the tension clamps and the
yokes remained irretrievable);
-The insulator strings were formed with composite insulators Hi Lite
EPG 400-160-4203-22, 95-NN20 type (manufactured by Eximprod Group
Buzau under Chance license);
-for the string make-up, we reused the existing fittings (yokes, ball eyes
OSDr-20) and the compression tension clamps,
- the new mounted strings were built-up so that the length of a new
string with spreader and a new string without spreader to be the same
with the length of an existing string, with or without spreader.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Before
After
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
LW technology
The works were complied with Transelectrica’s Operational Procedure
TEL 07.12/2003 „Performing Live Working in Transelectrica’s High
Voltage Equipments” and the technical procedures belonging to S.C.
Smart S.A.
The basic working team consisted of:
- A LW foreman with the authorization type I 3T.
- Eight (8) LW workers with the authorization type I 1T.
The work was executed by the bare hand
method
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
It is necessary that the equipment is in Special Exploitation Regime
(SER):
-verifying that the Differential Busbar Protection is in operation;
-ensuring radio or telephone connections between the working area and
the dispatch center;
-manually connecting to energize the equipment, can be done only with
the agreement of the foreman;
- it is forbidden to operate the switchgears in the substation, as this may
affect the status of the busbar.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Minimum Approach Distances
Rated
VoltageUn
[kV]
Voltage
distance dt
[m]
Safety
distance dp
[m]
Minimum
distanceD [m]
400
2,00
0,50
2,50
Weather Conditions
It is forbidden to start the work in the following weather
conditions:
- Showers (rain, snow, drizzle, hail,) or relative humidity higher
than 80%,
- Thick fog,
- Strong wind (over 9.5 m/s),
- Lightning (storm) in the working area.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Risk Analysis and Prevention Measures
-The foreman owns:
- the Working Authorization (ALST)
- the Technical Instruction (SMART-IT-LST 66)
- the Specific Safety Instruction (SMART-ISSM-66).
The foreman
- ensures that the equipment identifying conditions and the access
conditions in the working area are respected.
-indicates the way and the route for the workers to climb on the portal
and the way to manipulate the access tools
- is supervising the working area throughout the whole procedure.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Work Preparation
The foreman identifies the equipment on which the crew will work and
compares the working area with the one mentioned in the LW
authorization.
The foreman identifies the weather conditions in the working zone.
The tools and the devices are prepared on rack and on the canvas.
The insulating sections of the tools are cleaned and greased with
silicone oil. The 3 workers which will work at height will dress with
electro conductive suits, anti-UV goggles, electro conductive boots and
climbing systems.
The working tools and the safety devices are checked. The foreman also
checks the workers’ physical and psychical condition.
The foreman is distributing the specific tasks for each worker and is
reminding them of the work method and the risks which may occur. He is
checking that things are well understood by the crew.
The workers are signing the papers.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Working Method
Two workers are climbing on the crossarm. They will carry up and mount
the strain carriers on the crossarm.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
-The access ladder is mounted on the conductors.
- The mobile part of the ladder is descended on the ground.
-The worker climbs from the ground to the conductors, on the ladder. He
is fastening the mobile part of the ladder to the firm one.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
The workers are mounting the strain carrier assembly.
They are relieving strain from the insulating string, dismantling the
string.
The insulating string is descended to the ground.
The new insulation strig is raised and mounted. The strain is relieved
on strain carrier.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
Conclusions
It was for the firs time that a designer has thoroughly analyzed the
comparative costs for an investement project.
When starting a project it is mandatory to take into account the costs
involved by the working teams and by manipulation of devices, as well
as the costs of congestions, own technological consumption and
maneuvers.
One shouldn’t forget the advantages of network reliability, the increase
of work safety, less operating conditions demands for the transmission
network and the dispatch demands on the redundancy.
This was the first LW technology project performed in a Romanian
substation.
Sept, 2011, Salta CITTES 2011
Live Replacement of 400kv Busbar Insulators in Brasov Substation
THANK YOU FOR YOUR KINDLY
ATTENTION !
Sept, 2011, Salta CITTES 2011