PRISMIC ® T20 Power System Stabilizer0 pages

PRISMIC® T20
Power System Stabilizer
PRODUCT SPECIFICATION
Introduction
Power System Instability
Power system studies and many utility regulations require
additional excitation system control functionality to ensure that
generators contribute to power system stability.
Power system oscillations typically range from 0.1 to 3.0 Hz in
frequency and are commonly characterised as inter-area,
inter-unit or local modes of oscillation.
This functionality can be provided by power system stabilizers
(PSS) such as the BRUSH PRISMIC® T20.
Power fluctuations are directly related to the rotor angle
oscillations of a synchronous generator. Power system
stabilizers act on the excitation controller or AVR to adjust the
generator excitation to help reduce these rotor angle
oscillations.
The PRISMIC® T20 is a microprocessor based dual-input power
system stabilizer according to the IEEE 421.5 PSS2B model.
The stabilizer monitors generator terminal volts and current,
from which the operating variables of speed and electrical
power are derived.
The output of the T20 provides a bias to the reference signal
in the AVR. This provides damping of power system oscillations
by adjusting the generator field current.
The T20 is a compact unit with a steel enclosure designed for
securing to a cubicle mounting plate. It can be used as a retrofit
unit as well as being incorporated into new systems.
The T20 is suitable for connection to most automatic voltage
regulators for synchronous generators, with either brushless
or static excitation systems. It offers easy connection to any
analogue or digital AVR that has the capability to accept a
bipolar DC signal from a PSS.
It is also possible to transfer the bias signal of the PSS to an
AVR via a CAN-bus interface.
The user friendly, password protected, Windows based human
machine interface (HMI) software, accessed via an RS232 port,
ensures the T20 can be fully commissioned in any location.
Key Features
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Digital design.
Uses integral of accelerating power.
Based upon IEEE 421.5 PSS2B model.
Signal conditioning to minimise erroneous bias signal to the AVR.
Uses frequency behind generator reactance as speed signal.
Configurable gain setting.
Contains 3 lead/lag stages.
Isolated PSS output with clamp for protection.
Contains diagnostic and monitoring circuits - indications
available remotely via HMI, and locally via LEDs on the unit.
Analogue output port and CAN-bus interface to AVR.
PSS can be disabled via hardware and software.
Windows HMI commissioning software.
Data recording facility with automatic and manual triggers.
50 and 60 Hz operation.
CE compliant.
Suitable for brushless and static excitation systems.