allerection and precommissioning of switchyard equipments

7/27/2019 Allerection and Precommissioning of Switchyard Equipments

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ERECTION AND PRE

COMMISSIONING TESTING

OF EQUIPMENTS

BY

Y.SURYA PRAKASA RAO

Chief Manager



Receipt at site

After Receipt at site and before unloading

the materials ,the conditions of packing andrecord of the transportation shall be jointly

assessed by owner and contractor and dully

recorded.



Unloading and storage at site

Unloading

Unloading of materials should be done withcrane of suitable capacity using polyester

slings only.



Storage at site

Storage instructions should be followed strictly as

per storage instructions in equipment manual.

While shifting materials from storage place tofinal place for erection, sufficient care is to be

taken to avoid damage to the materials.

The material shall be opened after reaching

the place of erection .In case the material is found damaged during

storage and shifting. Inform supplier, erection

contractor and Insurance agency.



Storage at site

LA should be stored vertically.

CVT should be stored vertically.

CT should be stored vertically or if it ishorizantal, keep around 30 degree height

at top side.

WT should be stored vertically.Store all equipments above ground level by

making platforms.



ERECTION OF EQUIPMENTS

1. MEASURE FOUNDATION BOLTS DISTANCE &

LEVELING.

2. CHECK THE BASE PLATE HEIGHT WITH

EXISTING EQUIPMENT BASE PLATE.

3. CHECK THE LEVELING OF STRUCTURE AT TOP

WITH SPIRIT LEVEL AND TIGHT ALL NUTS &

BOLTS.

4. ERECT EQUIPMENT PREFERABLY WITH CRANEAS PER MANUFACTURER RECOMMENDATIONS.



ERECTION OF EQUIPMENTS

5. ERECT THE CT PRIMARY POINTS P1 &

P2 AS PER DRAWING.

6. ERECT LAS BY KEEPING VENTSDIRECTION AWAY FROM EQUIPMENTS.

7. ERECT ISOLATOR EARTH SWITCH

POSITION AS PER DRAWING.



PRE COMMISSIONING TESTS OF CT

1.POLARITY TEST.

2.MAGNETISATION CHARACTERISTICS OF CT.

3. RATIO TEST.

4.IR MEASUREMENT.

5. DGA TEST OF OIL.

6. TANDELTA & CAPACITANCE MEASUREMENT.



PRE COMMISSIONING TESTS OF CVT

1.POLARITY TEST.

2. RATIO TEST.

4. IR MEASUREMENT.5. TANDELTA & CAPACITANCE

MEASUREMENT



PRE COMMISSIONING TESTS OF SA

1. THIRD HORMONIC RESISTIVE

CURRENT.

2. IR MEASUREMENT OF INDIVIDUALSTACK.

3. OPERATION OF LA COUNTER.

4. TANDELTA & CAPACITANCEMEASUREMENT



PRE COMMISSIONING TESTS OF

ISOLATOR

1. MILLIVOLT DROP TEST.

2. IR MEASUREMENT .

3. 50 OPERATIONS TEST.



CONSTRUCTION FEATURES.

Circuit Breaker is an on load Switch

which can make & break load currents

and fault Currents in shortest time.

What it requires ?1.Support Structure.

2. Operating Drive Assembly.

3.Pole Column.

4.Interrupter.

5.Control Cubicle.



SUPPORT STRUCTURE

Lattice structure or Tripod.

It carries the operating drive assembly,pole

column and Interrupter .It will stand on the concrete foundations.



OPERATING DRIVE ASSEMBLY

It consists …

Pneumatic/hydraulic operating mechanism.

Compressor-motor/hydraulic pump.

Air-reservoir/ hydraulic reservoir.

Linkage mechanism.

Auxiliary switches.



POLE COLUMN

It consists… Stacks of support porcelain Insulators to insulate the live

parts from the ground.

Operating rod(Insulating rod) with guiding rings transmits

movement from driving assembly to moving contacts.

SF6 gas .

Shaft seal assembly seals the SF6 gas.



INTERRUPTER ASSEMBLY

Closing resistor assembly(optional)-400 ohms.

Grading capacitors(oil filled) -1200 PF .



TESTS

Pre-commissioning Tests.



PRE-COMMISSIONING TESTS

Pressure Switch settings of SF6 gas&Air/Oil.

Air/Oil Pressure drop tests during operation.

Air/Oil&SF6 gas Leakage tests in 24hrs.

Pole Discrepancy test for open/close.

Dew point & Air content tests for SF6 gas.

Milli volt drop test in close position.

Capacitance&Tan delta test for Grading Capacitor.Operation timings test.

Insulation Resistance measurement tests.



ROUTINE MAINTENANCE TESTS

SF6 gas&Air/Oil Pressure Switch settings.

Air/Oil Pressure drop tests during operation.

Pole Discrepancy test for open/close.

Operation timings test.

Dew point for SF6 gas. (Two yearly)

Milli volt drop test in close position.(Two yearly)

DCRM & Contact Travel Measurement tests.(Three yearly)

Capacitance&Tan delta test for Grading Capacitor.(four yearly)



OPERATION TIMINGS

•Close timings including PIR.

•Trip 1 timings .

•Trip 2 timings.

•Close Trip for both Trip 1 &2.

•Duty cycle operation times(O-0.3s-CO).

•Pole discrepancy time during open&close.



ACCEPTABLE/PERMISSIBLE LIMITS FOR

MAINTANANCE TEST RESULTS.

•CB operation timings. 400kv 220kv

-Closing time(max) 150Ms 200Ms

-Trip time(max) 25Ms 35Ms

-Close/Trip time

pole Discrepancy

phase to phase(max) 3.33Ms 3.33Ms

Break to Break(max)of same phase 2.5Ms 2.5Ms



•PIR TIMEBHEL make 12-16ms

CGL make 8-12ms

ABB make 8-10ms

NGEF make 8-12ms

M&G make 8-12ms

TELK make 8-12ms

ABB make(HVDC) 8-12ms



•PIR opening time prior to opening of main

contacts(ABB.CGL.NGEF make CBx) . 5ms(min)

AT RATED PRESSURE

•PIR and main contacts overlap time(BHEL,M&G,ABB imported)make CBx). 5ms(min)

AT RATED PRESSURE

•TAN DELTA of grading capacitors 0.007degrees at 20deg.cel.

•Capacitance of grading capacitors within +10 of the rated value

within – 5

•Contact resistance of CB 150 micro-ohm

•Contact resistance of CB terminal

Connector 10micro-ohm per connector



•IR value:

Phase earth 100m-ohm(min) by 5.0/10.0kvMEGGER

Across open contacts 1000m-ohm (min) by 5.0/10.0kvMEGGER

Control cables 50m-ohm(min)by 0.5kv MEGGER

•PRESSURE SWITCH SETTINGS

SF6 gas pressure switches within 0.1BAR OF SET VALUE

Operating air pr.switches within 0.1BAR OF SET VALUE

Operating oil pr.switches within 1.0 BAR OF SET VALUE



DEW POINT OF SF6 GAS

Make of CB Dew point at Corresponding Remarks

rated pr. Dew pt.at atmo.pr.

BHEL -15deg.cel. -36deg.cel. During commissioning

-7deg.cel. -29deg.cel. During O&M

-5deg.cel. -27deg.cel. CriticalM&G -39deg.cel During commissioning

-32deg.cel. During O&M

CGL -15deg.cel. -35deg.cel. During commissioning

-10deg.cel. -31deg.cel. During O&M

ABB -15deg.cel -35deg.cel. During commissioning

-5deg.cel -26deg cel. During O&M

NGEF -15deg.cel -36deg.cel. During commissioning

-7deg.cel. -29deg.cel During O&M

-5deg.cel -27deg .cel. Critical



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allerection and precommissioning of switchyard equipments

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