See discussions, stats, and author profiles for this publication at: https://www.researchgate.
net/publication/336373972
MV SYSTEMS VOLTAGE TRANSFORMER INSPECTION AND TEST PROCEDURE
Technical Report · October 2019
DOI: 10.13140/RG.2.2.33983.46244
CITATIONS READS
0 1,169
2 authors:
Ramadan Ali Ramadan Naguib
alfanar North Cairo Electricity Distribution Company
13 PUBLICATIONS 0 CITATIONS 12 PUBLICATIONS 1 CITATION
SEE PROFILE SEE PROFILE
All content following this page was uploaded by Ramadan Ali on 10 October 2019.
The user has requested enhancement of the downloaded file.
MV SYSTEMS
VOLTAGE TRANSFORMER INSPECTION AND TEST PROCEDURE
TABLE OF CONTENTS
VOLTAGE TRANSFORMER CHECKS
1) Visual Inspection
2) Winding resistance test
3) Insulation resistance test HV/LV/G
4) Ratio test
5) Polarity test
6) Check VT HV neutral solidly grounded
7) Verify secondary circuits, terminal to terminal for correctness and tightness
8) Loop resistance test and burden test
Page No.1 of 4 Prepared by: RamadanCLASSIFICATION:
Mohamed NaguibCONFIDENTIAL MVTC-VT-ITP
MV SYSTEMS
VOLTAGE TRANSFORMER INSPECTION AND TEST PROCEDURE
VOLTAGE TRANSFORMER CHECKS
1. Visual Inspection
♦ Inspect for physical damage / defects
♦ Check nameplate information for correctness
♦ Check that all grounding cables are securely connected
♦ Check color coded for secondary wiring and size of wires against specs.
♦ Check proper lugs has been used in termination
♦ Check VT’s location physically and secondary terminal labeling printed
2. Winding Resistance Test
♦ Check the VT Resistance at the VT terminals or at the Terminal Blocks in the
LV compartment using a ohm-meter.
A
a1
MILIOHM
METER
n1
a2
N
n2
VT RESISTANCE TESTING
ARRANGEMENT
3. Insulation Test
• Check the insulation resistance at the terminals with respect to ground / earth.
• The test voltage is 1000V DC for one minute.
A
a1
MEGGER
n1
a2
N
n2
INSULATION TESTING ARRANGEMENT
4. Ratio Check
• Apply one, 2 & 3 KV on VT primary terminal.
• Measure the corresponding out put on VT secondary terminal.
• Calculate VT turns ratio.
Page No. 2 of 4 Prepared by: RamadanCLASSIFICATION:
Mohamed NaguibCONFIDENTIAL MVTC-VT-ITP
MV SYSTEMS
VOLTAGE TRANSFORMER INSPECTION AND TEST PROCEDURE
A
a1 STEP UP
TRANSFORMER VARIAC
V SUPPLY
n1
AC
a2
V
N
n2
VT RATIO TESTING ARRANGEMENT
5. VT Polarity Checks
• Check the VT polarities on the LV compartment terminals as per the Schematic Drawing for
correct polarity.
A
a1
+
SWITCH A
- n1
+
BATTERY a2
-
N
n2
VT POLARITY TESTING ARRANGEMENT
6. Check VT HV Neutral Solidly Grounded
7. Verify Secondary Circuits, Terminal To Terminal For Correctness And Tightness
8. Loop Resistance Test And Burden Test
• Check the VT Loop Resistance with an ohmmeter at the extreme end terminals to ensure the
complete loop.
S1
S1
RELAY
S2
RELAY V
S2
A
OHMMETER
VOLTAGE
SOURCE
LOOP RESISTANCE MEASURING ARRANGEMENT BURDEN TEST ARRANGEMENT
Page No. 3 of 4 Prepared by: RamadanCLASSIFICATION:
Mohamed NaguibCONFIDENTIAL MVTC-VT-ITP
MV SYSTEMS
VOLTAGE TRANSFORMER INSPECTION AND TEST PROCEDURE
Page No. 4 of 4 Prepared by: RamadanCLASSIFICATION:
Mohamed NaguibCONFIDENTIAL MVTC-VT-ITP
View publication stats
