5.15. LOAD SHED FREQUENCY & POWER SET POINTS
The TSC 900 controller provides Frequency and Power (kW) sensing on the load of the ATS for
purposes of controlling the automatic Load Shedding feature. To enable these features, refer to
Option settings per Section 5.11.2 and Section 5.11.3. Load Shed can be configured to operate
when set points have been reached on bus under frequency and/or bus over power (kW)
conditions. When a Load Shed condition is activated, a yellow colored status light will be shown
on the GHC home page and a programmable output configured for Load Shed will be activated
to control an external system load to be automatically disconnected. Each load bus sensor is
individually programmable for pickup and dropout set points (i.e. adjustable hysteresis) in
addition to transient time delay settings. Refer to Section 3.4.4 for further details on automatic
Load Shed sequence of operation.
NOTES:
1. Load Shed operation based on Power (kW) is only available if
the ATS is equipped with CT’s on the load side of the ATS and
Power Metering operation is enabled.
2. Automatic Load Shed operation on either bus under frequency
or bus over power will only occur when the TSC 900 controller
Mode is set for “AUTO”. When the TSC 900 controller Mode is set
for “MANUAL or OFF” the Load Shed relay will not operate.
3. To disable Load Shed feature, Load Shed Initiate and
Reset timers must be set to zero
To program the sensing features, refer to the following descriptions:
5.15.1. LOAD SHED INITIATE DELAY
Once a transfer to Generator (SRC 2) condition is initiated, the Load Shed output will be
activated to shed non-essential load and the Load Shed Initiate time period will start
timing. Once the set time period expires, the Load Shed output will reset to allow the
non-essential loads to be re-energized (i.e. reset to normal). Select desired time in
seconds. If Load Shed is not required, set this time delay to zero.
5.15.2. LOAD SHED UNSHED DELAY
If a Load Shed condition had been activated by an abnormal set point threshold (i.e.
under frequency or over power) and the condition returns to normal, the Load Shed
Unshed time period will start timing. Once the set time period expires, the Load Shed
output will reset to allow the non-essential loads to be re-energized (i.e. reset to normal).
Select desired time in seconds If Load Shed is not required, set this time delay to zero.
To Next Page
Loading...
Need help?
General
