Description
FI810F The 745 is realized with digital hardware and software algorithms, using extensive internal
monitoring. Consequently, it is expected that, if the input circuits, CTs, VTs, power supply,
auxiliary signals, etc., are functioning correctly, all the protection and monitoring features
inside the relay will also perform correctly, as per applied settings. It is therefore only
necessary to perform a calibration FI810F of the input circuits and cursory verification of the
protection and monitoring features to ensure that a fully-functional relay is placed into
service.
Though tests are presented in this section to verify the correct operation of all features
contained in the 745, only those features which are placed into service need be tested.
Skip all sections which cover features not included or not enabled when the relay is in
service, except for the provision of the next paragraph.
Some features such as the Local/Remote Reset of targets, display messages and
indications are common to all the protection features and hence are tested only once.
Testing of these features has been included with the Harmonic Restraint Percent
Differential, which will almost always FI810F be enabled. If, for some reasons, this element is not
enabled when the relay is in service, you will need to test the Local/Remote Reset when
testing another protection element.
7.1.3 Safety Precautions
Ensure the following precautions are observed before testing the relay.
HIGH VOLTAGES ARE PRESENT ON THE REAR TERMINALS OF THE RELAY, CAPABLE OF
CAUSING DEATH OR SERIOUS INJURY. USE CAUTION AND FOLLOW ALL SAFETY RULES
WHEN HANDLING, TESTING, OR ADJUSTING THE EQUIPMENT.
DO NOT OPEN THE SECONDARY CIRCUIT OF A LIVE CT, SINCE THE HIGH VOLTAGE
PRODUCED IS CAPABLE OF CAUSING DEATH OR SERIOUS INJURY, OR DAMAGE TO THE
CT INSULATION.
THE RELAY USES COMPONENTS WHICH ARE SENSITIVE TO ELECTROSTATIC DISCHARGES.
WHEN HANDLING THE UNIT, CARE SHOULD BE TAKEN TO AVOID ELECTRICAL
DISCHARGES TO THE TERMINALS AT THE REAR OF THE RELAY.
ENSURE THAT THE CONTROL POWER APPLIED TO THE RELAY, AND THE AC CURRENT
AND VOLTAGE INPUTS, MATCH THE RATINGS SPECIFIED ON THE RELAY NAMEPLATE. DO
NOT APPLY CURRENT TO THE CT INPUTS IN EXCESS OF THE SPECIFIED RATINGS.
ENSURE THAT THE LOGIC INPUT WET CONTACTS ARE CONNECTED TO VOLTAGES BELOW
THE MAXIMUM VOLTAGE SPECIFICATION OF 300 V DC.
- All setpoints and actual values are mentioned with their path as a means of specifying
where to find the particular message. For instance, the setpoint WINDING 1 PHASE CT
PRIMARY, which in the message structure is located under setpoints page S2, would be
written as:
S2 SYSTEM SETUP WINDING 1 WINDING 1 PHASE CT PRIMARY
- Normal phase rotation of a three-phase FI810F power system is ABC.
- The phase angle between a voltage signal and a current signal is positive when the
voltage leads the current.
- Phase A to neutral voltage is indicated by Van (arrowhead on the “a”).
- Phase A to B voltage is indicated by Vab (arrowhead on the “a”).
- The neutral current signal is the 3I o signal derived from the three phase currents for
any given winding.
- The ground current is the current signal measured by means of a CT in the power
transformer connection to ground.
7.1.5 Test Equipment
It is possible to completely verify the 745 relay operation using the built-in test and
simulation features described earlier in this manual. However, some customers prefer to
perform simple signal-injection tests to FI810F verify the basic operation of each element placed
into service. The procedures described in this chapter have been designed for this purpose.
To use the built-in facilities, refer to the appropriate sections in this manual.
The conventional, decades-old approach to testing relays utilized adjustable voltage and
current sources, variacs, phase shifters, multimeters, timing device, and the like. In the last
few years several instrumentation companies have offered sophisticated instrumentation
to test protective relays. Generally this equipment offers built-in sources of AC voltage and
current, DC voltage and current, timing circuit, variable frequency, phase shifting,
harmonic generation, and complex fault simulation. If using such a test set, refer to the
equipment manufacturer’s instructions to generate the appropriate signals required by the
procedures in this section. If you do not have a sophisticated test set, then you will need
the following ‘conventional’ equipment:
- Variable current source able to supply up to 40 A (depends on relay settings)
- Variable power resistors to control current amplitude
- Ten-turn 2 kΩ low-power potentiometer
- Power rectifier to build a circuit to generate 2nd harmonics
- Accurate timing device
- Double-pole single-throw contactor suitable for at least 40 amperes AC.
- Combined fundamental and 5th-harmonic adjustable current supply for elements
involving the 5th harmonic.
- Variable-frequency source of current or voltage to test over/underfrequency and
frequency trend elements.
- Ammeters (RMS-responding), multimeters, voltmeters
- variable DC mA source
- variable DC mV source
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