Tap Changer; General; Setting Notes - Siemens 7SC80 Manual

2.22

Tap Changer

The tap changer or voltage regulator function can be used as a basic tap changer control or voltage regu-
lator control function and is intended to be used as part of a real-time SDFA Volt/VAR automation system. In
order to interface with the existing tap changer or voltage-regulator controls, hardwire connections will be
required between the existing units and the 7SC80 controller.
2.22.1

General

These hardwire connections include signal contacts from the 7SC80 to inhibit the existing tap changer or
voltage regulator controllers from initiating tap up or tap down control, as well as providing actual tap up and
tap down control. In addition, the voltage inputs are connected to the transformer or voltage-regulator secon-
dary side VTs, while the current inputs are connected to the transformer or voltage-regulator secondary CTs.
The voltage regulator function requires line end voltage signals supplied by a 7SC80 located at the line end.
These signals will provide the 7SC80 installed at the voltage regulator with upper and lower limit conditions
through "GOOSE" messages. The 7SC80 will thus control the voltage regulator in real-time based on the
reported line end voltage conditions. This SDFA automation system functionality can also be expanded to
include capacitor bank control.

Setting Notes

2.22.2
Tap Changer Settings
The tap changer is only effective and accessible if address 372 Tap Changer is set to Enabled. If this func-
tion is not required, Disabled is set.
The tap changer settings are located under the Setting Groups. The function should be activated at address
1250 Tap Changer.
Address 1251 T Pulse Tap Chg allows setting the tap up/down pulse duration in seconds.
Address 1252 T Dead CntPulse allows setting the tap up/down pulse duration in seconds.
The maximum number of consecutive tap up/down steps can be set at address 1253 MaxNo TChg UP and
1254 MaxNo TChg DOWN.
Address 1255 Tcrit. VoltLvl. allows setting the time interval that the tap changer will wait before
issuing the tap up command in the voltage reduction mode if the critical line end voltage is reached.
Modes of Operation
Auto mode for automatic generation of tap up/down commands in voltage restoration or voltage reduction
mode. In addition, this mode disables the manual control.
The voltage restoration (or voltage limit control) mode generates tap up/down commands to the tap change
mechanism in order to keep the voltage within the preset limits.
The voltage reduction mode generates tap down commands to decrease the line end voltage to a minimum
acceptable measured value during the voltage reduction process.
No. Information
2552
TapUpStepCnt
2553
TapDownStepCnt
2566
TapChg UpEnable
2567
TapChg Up
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Description
Counter counts consecutive steps. Any tap down step resets the counter.
Counter counts consecutive steps. Any tap up step resets the counter.
Allows the tap changer to issue tap up pulses. This input can be used to
block the tap up commands if voltage in the substation has reached the
maximum value and further tap up steps can cause overvoltage.
Manual tap up command. Tap changer issues a single tap up pulse if Auto
mode is OFF.
Functions
2.22 Tap Changer
351