7SG15 MicroTAPP Description of Operation
©2013 Siemens Protection Devices Limited
Chapter 1 Page 2 of 38
Contents
1
Introduction....................................................................................................................................... 4
2
Power system requirements............................................................................................................. 4
3
MicroTAPP Functionality.................................................................................................................. 4
3.1
Inputs.......................................................................................................................................... 4
3.1.1
Voltage Measurement........................................................................................................ 5
3.1.2
Current Measurement........................................................................................................ 5
3.1.3
Status................................................................................................................................. 5
3.2
Outputs ....................................................................................................................................... 5
4
Description of operation ................................................................................................................... 6
4.1
General....................................................................................................................................... 6
4.2
Transformers in Parallel ............................................................................................................. 8
4.2.1
Circulating Current Control ................................................................................................ 8
4.2.2
Negative Reactance circulating current control – TAPP ................................................. 10
4.2.3
Master/Follower control ................................................................................................... 11
4.3
Load Drop Compensation ........................................................................................................ 11
4.4
MT102 Advanced Features ...................................................................................................... 11
4.4.1
Description of Operation.................................................................................................. 11
4.4.2
Location of tap-changer, HV or LV side........................................................................... 12
4.4.3
Change in voltage per tap ............................................................................................... 12
4.4.4
Single phase or 3 phase units ......................................................................................... 13
4.4.5
Direction of tap-changer for voltage increase.................................................................. 13
4.4.6
Transformer impedance .................................................................................................. 13
4.4.7
Nominal voltage or winding load drop compensated target settings............................... 13
4.4.8
Dead-Reckoning Block .................................................................................................... 13
4.4
MicroTAPP–MicroTAPP communications................................................................................ 13
4.5
Low Frequency Voltage Reduction .......................................................................................... 13
4.6
Transformer Switch out ............................................................................................................ 13
4.7
Transformer Switch in .............................................................................................................. 14
4.8
Relay Settings .......................................................................................................................... 14
4.8.1
Basic Set-point................................................................................................................. 14
4.8.2
Normal voltage deadband ............................................................................................... 14
4.8.3
Load Drop Compensation (LDC) ..................................................................................... 14
4.8.4
Circulating Current Compensation .................................................................................. 15
4.8.5
Tap Stagger ..................................................................................................................... 15
4.8.6
Time Delays for Operation............................................................................................... 15
5
Control............................................................................................................................................ 15
5.1
Control Points........................................................................................................................... 15
5.1.1
At the tap change mechanism ......................................................................................... 15
5.1.2
At the voltage control relay panel .................................................................................... 16
5.1.3
At a remote site................................................................................................................ 16
5.2
Control Switches ...................................................................................................................... 16
5.2.1
Local/Remote................................................................................................................... 16
5.2.2
Auto/Manual..................................................................................................................... 16
5.2.3
Raise/Lower..................................................................................................................... 16
6
Protection ....................................................................................................................................... 17
6.1
Voltage and Current ................................................................................................................. 17
6.1.1
Measured voltage outside normal range ......................................................................... 17
6.1.2
Voltage transformer faulty ............................................................................................... 18
6.1.3
Load Current.................................................................................................................... 19
6.2
Tap Changer ............................................................................................................................ 19
6.2.1
Tap Change Runaway..................................................................................................... 19
6.2.2
Tap Change Incomplete .................................................................................................. 20
6.2.3
Limit of Tap Change Range............................................................................................. 20
6.2.4
Tap Not Achievable ......................................................................................................... 20
7
Other Features ............................................................................................................................... 21
7.1
Instrumentation and Metering................................................................................................... 21
7.1.1
System ID ........................................................................................................................ 21