CT-VT tandelta measurement
REV.0
TD5000 - TDX5000
Current and Voltage transformers
TanDelta measurement
Doc. CT-VT tandelta measurement
Rev. 0
Page 2 of 6
Introduction
The following document describes the measuring method of Tandelta values for current and voltage transformers.
CURRENT TRANSFORMER: 1ST CASE
The ground screen can be disconnect from the ground.
Connections
1.
2.
3.
4.
High voltage cable connected to the primary side
IN_A connected to the shield
IN_B connected to the bushing using hot collar
CT secondary windings short-circuited to the ground
Mode
The testing mode to use it UST_A
Test
1. Voltage sweep at 50Hz, starting from 100V
2. Frequency sweep at 100V, starting from 15Hz to 500Hz
Schematic
CH
Doc. CT-VT tandelta measurement
Rev. 0
Page 3 of 6
CURRENT TRANSFORMER: 2ND CASE
The ground screen cannot be disconnected from the ground.
Connections
1. High voltage cable connected to the primary side
2. IN_B connected to the bushing using hot collar
3. CT secondary windings short-circuited to the ground
Mode
The testing mode to use it GSTgA+B
Test
1. Voltage sweep at 50Hz, starting from 100V
2. Frequency sweep at 100V, starting from 15Hz to 500Hz
Schematic
CH
Doc. CT-VT tandelta measurement
Rev. 0
Page 4 of 6
CURRENT TRANSFORMER: 3RD CASE
There is no ground shield.
Connections
1. High voltage cable connected to the primary side
2. IN_A connected to the CT secondary windings (short-circuited)
3. IN_B connected to the bushing using hot collar
Mode
The testing mode to use it UST_A
Test
1. Voltage sweep at 50Hz, starting from 100V
2. Frequency sweep at 100V, starting from 15Hz to 500Hz
Schematic
CH
Doc. CT-VT tandelta measurement
Rev. 0
Page 5 of 6
VOLTAGE TRANSFORMER: 1ST CASE
Neutral point of primary side can be disconnected.
Connections
1. High voltage cable connected to the primary side
2. IN_A connected to the VT secondary windings (short-circuited)
3. IN_B connected to the bushing using hot collar
Mode
The testing mode to use it UST_A
Schematic
N
Doc. CT-VT tandelta measurement
Rev. 0
Page 6 of 6
VOLTAGE TRANSFORMER: 2ND CASE
Neutral point cannot be disconnected.
Connections
1. High voltage cable connected to the primary side
2. IN_A connected to the VT secondary windings (short-circuited)
3. IN_B connected to the bushing using hot collar
Mode
The testing mode to use it UST_A
Schematic
N