ABB Relion 670 Series Applications Manual page 398

Section 15
Control
If there is no voltage supervision, then set the corresponding inputs as follows:
• VOLT_OFF = 1
• VOLT_ON = 0
15.5 Voltage control
15.5.1 Identification
Function description
Automatic voltage control for tap
changer, single control
Automatic voltage control for tap
changer, parallel control
Tap changer control and supervision,
6 binary inputs
Tap changer control and supervision,
32 binary inputs
15.5.2 Application
When the load in a power network is increased the voltage will decrease and vice versa. To
maintain the network voltage at a constant level, power transformers are usually equipped
with on-load tap-changer. This alters the power transformer ratio in a number of predefined
steps and in that way changes the voltage. Each step usually represents a change in voltage of
approximately 0.5-1.7%.
The voltage control function is intended for control of power transformers with a motor driven
on-load tap-changer. The function is designed to regulate the voltage at the secondary side of
the power transformer. The control method is based on a step-by-step principle which means
that a control pulse, one at a time, will be issued to the tap changer mechanism to move it one
position up or down. The length of the control pulse can be set within a wide range to
accommodate different types of tap changer mechanisms. The pulse is generated whenever
the measured voltage, for a given time, deviates from the set reference value by more than the
preset deadband (degree of insensitivity).
The voltage can be controlled at the point of voltage measurement, as well as at a load point
located out in the network. In the latter case, the load point voltage is calculated based on the
measured load current and the known impedance from the voltage measuring point to the
load point.
The automatic voltage control can be either for a single transformer, or for parallel
transformers. Parallel control of power transformers can be made in three alternative ways:
• With the master-follower method
• With the reverse reactance method
• With the circulating current method
392
IEC 61850
identification
TR1ATCC
TR8ATCC
TCMYLTC
TCLYLTC
© Copyright 2017 Hitachi Power Grids. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
90
U
IEC10000165 V1 EN-US
90
U
IEC10000166 V1 EN-US
- 84
- 84
1MRK 511 401-UEN Rev. K
SEMOD158732-1 v3
SEMOD173054-2 v5
SEMOD159067-1 v2
SEMOD159053-5 v6
Bay control REC670
Application manual