Capacitor Control; Modes Of Operation; Setting Notes - Siemens 7SC80 Manual

Functions

2.21 Capacitor Control

2.21 Capacitor Control
The capacitor bank control function can be used to control capacitor banks in various applications and is
intended to be used as part of a real-time SDFA Volt/VAR automation system.

Modes of Operation

2.21.1
The capacitor bank control function includes the following applications:
•
In standalone mode configuration, the capacitor bank control uses the locally measured voltage and
sends an ON CMD to the capacitor bank if the local voltage drops below the set threshold. In turn, if the
voltage rises above the overvoltage threshold due to a load decrease or any other system event, the
capacitor bank control creates an
alone mode does not require communication to any other devices in normal operation. However, when
used as part of a complete SDFA Volt/VAR system, this mode of operation is activated if a device loses
connection to the rest of the system.
•
In real-time line end voltage mode, the capacitor banks are operated on the basis of the voltage at the
line end, in contrast to the local voltage. In this configuration, a remote device, installed at the line end,
can measure the voltage and communicate to the capacitor bank control function via "GOOSE" messages,
providing real-time remote under-/overvoltage indications. The capacitor bank is activated via an
to support the line end voltage if the control device receives an undervoltage indication. In turn, the
control disconnects the capacitor bank if an overvoltage condition has been detected and reported by the
line end device. Therefore, it is not necessary to estimate or predict the operation based on seasonal or
time of the day loading estimates when using this application.
•
Real-time capacitor bank control using the power factor from the head end device and line end voltage
information. In this configuration, the capacitor bank control function communicates with the head end
device to receive real-time power factor information as well as with the line end device to receive the
voltage limits. The capacitor bank can be activated (
voltage is below the set limit. In order to disconnect the capacitor bank, conditions can be configured to
either use the overvoltage indication from the line end or the head end device indication if the amount of
VAR exported by the feeder is greater than the set threshold.
•
The capacitor bank control function can be used in combination with the tap changer or voltage regu-
lator functions to create a complete real-time SDFA Volt VAR optimization system. In this configuration,
the capacitor bank control receives the system mode of operation along with the real-time line end
voltage and power factor data. Based on this information and the system conditions, the capacitor bank
control can employ more complicated algorithms to operate the pole-top capacitor banks. It can thus be
activated to correct the power factor, bringing it closer to unity during the voltage reduction process. The
standalone mode is activated if the device loses connection to the rest of the system.

Setting Notes

2.21.2
Capacitor Bank Control Settings
The capacitor bank control is only effective and accessible if address 371 Capacitor Ctrl. is set to
Enabled. If this function is not required, Disabled is set.
The capacitor bank control settings are located under the Setting Groups. The capacitor bank control should
be activated at address 1240 Capacitor Ctrl..
Address 1241 T Startup allows configuration of the setting time between the initial startup, and the OFF
command issued to synchronize the internal feedback with the capacitor bank status.
Address 1242 TD ON Command sets the time interval between ON commands that can be issued by the
capacitor bank control. This setting is used to slow down the capacitor bank operation and to minimize the
number of switching operations.
Address 1243 T ON/OFF CMD allows setting of the required ON/OFF command pulse width.
348
OFF CMD to disconnect the capacitor bank from the grid. The stand-
ON CMD ) if the power factor is low or the line end
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
ON CMD