Features; Application; Transformer Configuration And Applicable Model - Toshiba GRT100 Manual

GRT100

FEATURES

Fully numerical transformer protection
Current differential protection for two-winding
or three-winding transformers
High-set differential overcurrent protection
No interposing CTs required
CT ratio and vector group compensation
Restricted earth fault protection
Time-overcurrent protection
Thermal overload protection
Overexcitation protection
Frequency protection
Configurable binary outputs
Automatic monitoring
Metering and recording functions
Menu-driven user interface
Two serial ports for a local PC and a remote PC
IRIG-B port for external clock

APPLICATION

GRT100 is a numerical transformer protection relay,
which can be applied for two-winding or three-winding
power transformers, auto-transformers and generator-
transformer units.
GRT100 provides the following protection schemes.
The current differential protection is applied for fast
and selective main protection. This protection
requires no interposing CTs and provides stability
against magnetizing inrush and overexcitation.
The restricted earth fault protection detects internal
earth faults where the transformer star point is
directly or low impedance earthed and can be applied
on high-voltage and low-voltage side respectively.
The time-overcurrent protection is mainly used as
backup protection and can be applied on high- and
low-voltage side respectively.
The thermal overload protection protects the
insulation against thermal stress and provides two
independently set levels for alarm and tripping.
The overexcitation protection provides alarm and
tripping.
The frequency protection operates on over-
frequency and underfrequency and provides load
shedding.
GRT100 provides the following metering and
recording functions.
Metering (current, voltage, frequency)
Fault recording
Event recording
Disturbance recording
GRT100 provides the following user interfaces for
relay setting or viewing of stored data.
Relay front panel: LCD, LED display and operation
keys
Local PC
Remote PC
The relay can be accessed from a local PC or a
remote PC through communication ports.
A local PC can be connected to the relay via the
RS232C port on the front fascia of the relay and a
remote PC can be connected to the relay through the
RS485 port at the rear of the relay.
GRT100 has two models which differ according to the
number of three-phase current inputs for differential
protection.
Model 100 - For 2-winding transformers requiring
2 three-phase current inputs
Model 200 - For 3-winding transformers and all
power transformers requiring 3 three-
phase current inputs

Transformer configuration and applicable model:

Configuration No. of current
inputs
HV
LV
HV
LV1 LV2
HV
LV
HV
LV
2
Applicable to:
2 Model 100
3 Model 200
3 Model 200
3 Model 200