1)All Manual Holder

VERSION NO.: 1
REVISION NO.: FIELD CHANGE
FIELD CODE:
DATE
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WORK INSTRUCTION PROCESS FOR INSPECTION, TESTING & COMMISSIONING OF ELECTRICAL SWITCH BOARD & SWITCHYARD

PREPARED BY

/ LEGALIZED BY
______
PROJECT DIRECTOR / ______
QMR
SIGNATURE: / SIGNATURE:
DATE: 2 APRIL 1998 / DATE
APPROVED BY:
SIGNATURE:
DATE: / ______
ELECTRICAL DIVISION MANAGER
Amendment record
Page No. / Rev. No. / Description of Amendment / Date of issue / QMR Legalized Date / Electrical Authorized Date
N/A / N/A / First Issue of WI016, Ver. 1 & Rev. 0 for
PT ______
N/A / N/A / Page OF 22
Revision 1
Battery & Battery Charger Inspection Record Incorporated

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1)ALL MANUAL HOLDER

WORK INSTRUCTION PROCESS FOR INSPECTION, TESTING & COMMISSIONING OF ELECTRICAL SWITCH BOARD & SWITCH YARD

PURPOSE

SCOPE

RESPONSIBILITIES

DEFINITIONS

PROCEDURES

5.1GENERAL

5.2POLARITY CHECKS

5.3RATIO CHECKS

5.4MAGNETIZATION CURVE

5.5VOLTAGE TRANSFORMER TEST

5.6RATIO CHECK

5.7PHASING CHECK

5.8SECONDARY INJECTION

5.9HI-POT TESTING USING FERRANTI HI-POT SET

5.10HI-POT TESTING USING BIDDLE HI-POT TEST SET

5.11EARTH RESISTANCE TEST (ET5) TO AS3000

5.12DUCTER TESTING (SWITCH GEAR)

5.13BLOCK DIAGRAM OF COMMISSIONING HV SWITCH YARD

5.14BLOCK DIAGRAM OF COMMISSIONING HV SWITCH BOARDS

5.15MIDOS RELAY TYPES

5.16COMMISSIONING CHECK LIST

QUALITY RECORDS

1.0PURPOSE

1.1To ensure testing carried out in Switch Yards and Switch Boards is done so in a planned acceptable manner.

2.0SCOPE

2.1This procedure applied to the testing of all switch gear undertaken by PT ______Technical Services Division except if otherwise directed by the Client.

3.0DEFINITIONS

The ClientMain Contractor

4.0RESPONSIBILITIES

4.1The Technical Services Supervisor is responsible for:

(a)Coordination of inspection activities

(b)Ensuring test reports are sent out to clients.

4.2Technical Services Technicians are responsible for carrying out tests as directed in accordance with these procedures, and recording the test or inspection results on the correct form.

5.0PROCEDURES

5.1General

5.1.1All results of equipment tested shall be recorded on the relevant test sheet, refer Section 5.0, copies being in Procedures Manual PM2.

5.1.2All equipment used for inspection and testing shall carry a current calibration sticker is not affixed, contact the Technical Services Supervisor.

5.1.3If any equipment should fail inspection and/or testing, the client will be notified at the time of testing or, if not available, at the earliest possible time.

5.1.4A test report will be issued to the Client for all inspection and testing undertaken if the specified in the contract or on request from the Client.

5.2Polarity Checks

Each current transformer should be individually tested to verified that the primary and secondary polarity markings are the same as drawings supplied by client.

At current transformer terminals in Protection/Metering Panel. The Protection/Metering Terminal identification is as follows:

C10 This is Red Phase over-current or earth fault protection
C30 This is Yellow Phase over-current or earth fault protection
C50This is Black Phase over-current or earth fault protection
C70 This is Neutral over-current or earth fault protection

A10 or A110This is Red Phase differential protection

A30 or A130This is Yellow Phase differential protection

A50 or A150This is Black Phase differential protection

A70 or A170 This is Neutral differential protection

D10This is Red Phase metering

D30This is Yellow Phase metering

D50This is Black Phase metering

D70This is Neutral Metering return

NOTE:The above identifications always starts with A, C or D but the numbers may be slightly different. The numbers always use 10, 30 and 50 but maybe the number is C110. This is done when there are several protection schemes on the same feeder.

Method

Connect polarity test set as per drawing, Fig. 1, by pushing test button down, a positive flick on the meter should occur. If this does not occur follow check chart below.

FIGURE 1 POLARITY CHECK

Check list Meter Polarity Incorrect

Check drawing for correct P1-P2 directions

Check connection on polarity test set

NO FLICK ON METER

Open lines on C T Terminals

Check you have to correct numbers (ie C10 and C11)

5.3Ratio Checks

This check is usually carried out to verify the ratio of the CT to the drawings. Current is passed through the primary conductors and measured by means of the test set ammeter or CT used in conjunction with the test set A1. The secondary current is measured on the ammeter A2 in Figure 2 and A2 + A3 in Figure 3.

FIGURE 2 CURRENT TRANSFORMER CHECKS (SINGLE PHASE)

FIGURE 3 CURRENT TRANSFORMER CHECKS (TWO PHASES)

IMPORTANT:When injection of current is taking place make sure, if there is more than 1 CT in that Phase that the CT’s not in test are shorted out and not open circuit.

5.4Magnetization Curve

This test is carried out when commissioning to,

verify the CT is manufactures specs,
check that when the equipment has been assembled they have been wired correctly, ie over-current and differential are correctly wired.

When checking aboard with metering, over-current and differential the knee point curve should be very low with saturation flux as low as 20-30V were as the over-current voltage will be around 120V to 180V. Differential CT’s have a knee point around 500V upwards.

Types of CT’s used,

Class 1= Metering CT’s

IOP50= Over-current type CT’s

005P2O= Differential type CT’s

FIGURE 5 TESTING CURRENT TX MAGNETISING CURVE

METHOD

Several points must be checked on each CT. This is done through a variable transformer while the primary CT circuit remains open. See Figure 5. The magnetizing current is measured on the ammeter A and the secondary voltage using a voltmater. The applied voltage would be slowly raised until the magnetizing current is seen to rise rapidly (50% increase in current to 10% increase in voltage), for a small increase in voltage. This indicates the approximate knee point of the CT. The magnetizing current should be recorded using Technical Service sheets.

It is often found that the current transformer with a secondary rating of 1 ampere or less have a knee point voltage higher than the legal main supply. In this case a step up transformer may be required to obtain the necessary voltage to check the curve.

5.5Voltage Transformer Tests

The voltage transformer polarity can be checked with the test described for the main current transformers, care must be taken to connect the battery supply to the primary winding, with the polarity ammeter connected to the secondary winding if the voltage transformer is of the capacitor type, then the polarity of the transformer at the bottom of the capacitor stack should be checked.

5.6Ratio Check

This check is carried out on HV voltage transformers to verify the ratio is correct.

Method

As in Figure 6 22kV side of transformer is energized using 415V. Readings should be taken on LV side phase to phase to neutral. Taking the ratio into consideration the voltage on the secondary of a 22000V/110V transformer should be phase 2.08V and phase to neutral 1.20V.

FIGURE 6 VOLTAGE RATIO TEST

5.7Phasing Check

The secondary connections for a three phase voltage transformer or a bank of three single voltage transformers must be carefully checked for phasing. With the main circuit alive, the secondary voltages between the phases and neutral must be measured for correct magnitudes. The phase rotation should then be checked with a phase rotation meter connected across the three phases, as shown in Figure 7. Provided an existing proven VT is available on the same primary system and that the secondary earthing is employed, all that is now necessary to prove correct phasing is a voltage check between, both “A” phase secondary outputs, there should be normally little or no voltage if the phasing is correct. B&C phase should be checked also, this proves the system by means of secondary phasing checks.

FIGURE 7 TRANSFORMER PHASING CHECK

5.8Secondary Injection

These test are generally described in the manufactures service manual for relays, but brief details are given below for the main types of protection relays.

Equipment

It is common practice to provide test blocks or test sockets in the relay circuits so that connections can readily be made to test without disturbing wiring. A later development was the test plug which can be used to plug into draw-out relay case or into test block nominated near to a non draw-out relay case.

When used with a draw-ou relay the multiple figures of the test plug are inserted between the contract stripes of the case and the draw-out chassis are normally spinning together to make firm contact.

Since the top and bottom contact or each test plug finger is separated by an insulation strip to relay circuits can be completely isolated from the switchgear wire when the test plug is inserted, ie is most important to remember, that the correct transformer shorting switches, will not be shorted links are fitted across all live side CT terminals of the test plugs before it is inserted. When the test plus is inserted in position all the test circuitry can now be connected to the isolated ‘Relay Side’ test plug terminals.

Withdrawing the test plug immediately restores the connections to the main current transformers and voltage transformers removed is the test connections and also the short circuits which had been applied to the main CT secondary circuits.

A recent development has been the testing facilities provided for the modular type case. The heavy current connectors at the extreme right hand side of the case are normally connecting the main A.C. and D.C. incoming supplies to the relay and hold open short circuiting switches provided in the case to prevent CT secondary circuits from being open circuited.

When these connections are removed, the relay is isolated and the main current transformer incoming connections are automatically short circuited.

A test plug may then be inserted so that secondary injection test can take place. As previously described for the draw-out case, care must be taken then inserting plug as the CT terminals are open circuited. As previously described CT terminals must have shorting links in before plug is inserted. The relay is now isolated for testing in the case of an MCGG63 (over-current and earth fault relay) terminals 13 and 14 must be linked, 15 and 16 must be linked this give the relay its supply. Care must be taken to make sure 13 is positive and 14 is negative at relay terminals.

5.9Hi-Pot Testing using Ferranti Hi-Pot Test Set

Cable testing as per AS 1026 & AS 1429

5.9.1Insulation Test (Before)

For a XLPE cable, which is individually screened each core should be tested between screen and core. Results should be in the high Meg-ohms. Each test should be for 1 minute.

For cables which are not individually screened, each core should be tested to earth with the other cores at earth potential. Results should be in high Meg-ohms. Each test, should be 1 minute.

The above test should be carried out using test report number------.

5.9.2HV Test

(a)Core to Screen Test

For core to screen test, connect HV probe into negative output of test set. Connect HV prove to core under test, and earth to screen of cable. Turn on key switch, then HV switch. HV light should be on. With voltage control knob wound back fully anticlockwise, a micro switch should be heard operating. Slowly wind knob clockwise, observe voltage increase and milliamp meter. Once required voltage has been reached, time test for period specified. Discharge cores after each test, using discharge stick.

(b)Core to Core Test

For core to core testing, connect HV probes into negative and positive outputs of test set. Connect earth of test set to earth on cable. Connect probes to cores under test, making sure spare core is connected to positive output of test set. Turn on key switch, then HV switch, HV light should be on. With voltage control know wound back fully anticlockwise, a micro switch should be heard operating. Slowly wind know clockwise, observing voltage increase and milli-amp meter. Once required voltage has been reached, time test for period specified. Discharge cores after each test, using discharge stick.

5.9.3Insulation Test (After)

For a XLPE cable, which is individually screened, each core should be tested between screen and core. Results should be in the high Meg-ohms. Each test should be for 1 minute.

For cables which are not individually screened, each core should be tested to earth with the other cores at earth potential. Results should be in the high Meg-ohms. These test should be for 1 minute.

5.9.4Cable Test Voltage after Insulation

Voltage Designation kV /

Belted Cables

/ Single Cores & Screened Cables
Between Conductors kV / Between any Conductor & Shealth kV / Between any Conductor & Sheath kV
0.6/1 / 3.5 / 3.5 / 3.5
1.9/3.3 / 10 / 7.0 / 7.0
3.8/6.6 / 20 / 15.0 / 15.0
6.35/11 / 34 / 25 / 25.0

NOTE:1) Testing time of each core should be 15 minutes per core

2)For each repeat Hi-Pot Test, carried out on the same cable, reduce voltage by 20%.

3)AS 1026 impregnated paper insulated cables

4)AS 1429 Polymeric Insulated cables up to 19/33kV (XLPE)

5.9.5Safety Warnings

(a)Make sure, cable clearances are followed, Eg: Core to core clearance, and core to earth are far enough apart to stop flash over during HV Tests.

(b)Place danger sings at both ends of cable, warning Personnel of High Voltage testing.

(c)Place barriers around both ends of cable preventing Personnel from entering test area.

(d)If cables is in a situation where Personnel could come in contact with it, or if it would be safer to have someone at the open end, do so.

(e)Take time in carrying out test, as High Voltage test sets have the potential to KILL.

(f)Always discharge cables after each test.

5.10Hi-Pot Testing using Biddle Hi-Pot Test Set

Cable testing as per AS 1026 & AS 1429

5.10.1Insulation test of cable (Before)

For a XLPE cable which is individually screened, each core should be tested between screen and core. Results should be in the high Meg-ohms. Each test should be for 1 minute.

For cables which are not individually screened, each core should be tested to earth with the other cores at earth potential. Results should be the high Meg-ohms. Each test should be for 1 minute. The above test should be carried out using test report number ------.

5.10.2HV Test

(a)XLPE Individually Screened Cables

Connect HV probe to cable. With foot switch in position and depressed, set dial to zero, this allows HV to be energized. Turn dial clockwise, observing kV and mili-amp meters, until required voltage is reached. Carry out test to all three cores individually. After each test discharge cores using discharge stick.

(b)Unbelted Cables

Connect HV probe to core. Short other cores to earth. With foot switch in position and depressed, set dial to zero, this allows HV to be energized. Turn dial clockwise observing kV and milli-amps meters, until required voltage is reached. Carry out test to all three cores individually. After each test discharge cores using discharge stick.

NOTE: FOLLOW WARNING GIVEN ON TESTING

5.10.3Insulation Test of Cables (After)

For a XLPE cable which is individually screened each core should be tested between screen and core. Results should be in the high Meg-ohms. This test should be for 1 minute.

For cables which are not individually screened each core should be tested to earth with the other cores at earth potential. Result should be in the high Meg-ohms. This test should be for 1 minute.

5.10.4Cable Test Voltage after Installation

Voltage Designation kV /

Belted Cables

Note:1. Testing time of each core should be 15 minutes per core.

2. For each repeat Hi-Pot test carried out on the same cable reduce

voltage 20%.

AS 1026 impregnated paper insulated cables.

AS 1429 Polymeric insulated cables up to 19.33 kV (XLPE)

5.10.5Safety Warnings

(a)Make sure cable clearance are followed. Eg: Core to core clearances, and core to earth are far enough apart to stop flash over during HV tests.

(b)Place Danger signs at both ends of cable warning Personal of High Voltage testing.

(c)Place barriers around both ends of cable, preventing Personal form entering test area.

(d)If cable is in a situation were Personnel could come in contract with it, or if it would be safer to have someone at the open end, do so. Take your time in carrying out test as High Voltage test sets have the potential to KILL.

5.11Earth Resistance Test (ET5) To AS3000

5.11.1Normal Method of Test

Join terminal C1 an dP1 together connecting a lead to the electrode under test. The length of this lead should be kept to a minimum, as this will affect the electrode. P2 lead can be connected to electrode which should be between 15 and 25m from test point. C2 lead can be connected to an electrode 15 to 25 meters away form P2. This must be kept in a line so P2 can pick up the volt drop between electrode under test (C1) and C2.

5.11.2Fall of Potential Method

Join terminals C1 and P1 together connecting a lead to the electrode under test. The length of this lead should be kept to a minimum, as this will affect the electrode resistance. Lead resistance can be deducted by running two leads for P1 and C1 to the electrode. P2 connection to spike should be 25m away from electrode under test. C2 should then be placed 25m from P2 in a straight line. After a test has been carried out at this point P2 should be moved about 3m either side of centre. If the first resistance is the same as the first reading, or close to it. The mean value is used as the earth resistance. If the readings are completely difference then the test using the 62 feet and 100 feet should apply.

5.11.3The 62% Rule for Single Earth Systems

It is normal, to carry out the measurement of electrode resistance by full of potential method! The 62% Rule involves positioning of potential spikes P and C at intervals of 62 feet and 100 feet. Connecting cables to earth tester to complete the current and voltage under test. To obtain a true reading, the current spike must be correctly placed in line with electrode under test. Since both electrode under test and C2 must be sufficiently apart to stop resistance are of both spikes overlapping.

Graphically it can be demonstrated that:

The true resistance of the electrode to be tested is equal to the measured resistance when the potential electrode is at a distance from the electrode. This should be equal to 62% of the distance from the earth electrode to the current electrode C2.

NOTE: This rule can only apply when all electrodes are in line and the earth is a single electrode, pipe or plate.