Electronic Relay

FEATURES

• Software based design

• Very sensitive and wide setting range

• Insensitive to currents at harmonic frequencies

• Trip test facility

APPLICATION

Restricted earth fault protection of transformers, generators and motors differential protection of bus bars, motors and generators.

PRINCIPLE OF OPERATION

Type JRD Oil & JRD 013 are basically a current operated, software based, differential relays which works on the high impedance principle. An external series stabilizing resistor is used with this relay to make it a voltage operated relay. The voltage setting of the relay is adjusted to be higher than that developed by the current transformers used maximum external fault conditions. JRD Oil is a single pole relay where as JRD 013 is a triple pole relay.

the fundamental frequency. The output of the filter is fed to a voltage comparator. When the sensing current signal at the fundamental frequency exceeds the set value, the comparator gates a train of pulses to the pro­cessor. The program residing in the CPU (central processing unit) performs the function of control and also gives output signals for relay and LED ( Light Emitting Diode) driver circuits. The operation of the relay is indicated by the glowing of a 'Red' LED , which has to be reser manually by means of a 'RESET' push button provided on the front of the relay. A 'Trip Test' push button is also provided in the relay to enable test­ing of the trip and alarm circuits.

The relay will not operated at third harmonic currents upto 25 times the setting.

TECHNICAL DATA

Features

• No Auxiliary supply

• Programmable operating characteristics

• Low burden

• Wide setting range

• LED fault flag indication

Application

• JRC 966SP provides three pole phase over current protection for distribution feeder and transformer. The relay measures the line current. If it exceeds a set thre shold value, then the relay extends a trip signal according to the selected characteristic.

• JRC 962SP provides earth fault protection for distribution feeder and transformer. The relay measures earth fault current. If it exceeds a set threshold value, then the relay extends a trip signal according to the selected characteristic.

• JRD 91 ISP provides neutral over current protection for a star connected transformer. The relay measures fundamental frequency component of current and if it exceeds the set threshold, then relay extends a trip signal instantaneously. The relay is insensitive to switching harmonics.

• All the above mentioned relays derives power supply from line CT's through 10 module and hence does not require any auxiliary supply for it's operation. Therefore, these relays are ideally suited for all applications where auxiliary supply is not available such as RMU's and unattended substations.

FEATURES

• Software based design

• DIP switch settings

• Wide setting range

• Choice four curves

• Instantaneous high set

• Very low burden

APPLICATION

Time graded protection of generators, Transformers, capacitors etc;

TECHNICAL DATA

FEATURES

• Software based design

• Instantaneous / Definite time

• Wide range of battery voltage

• Solid state reliability

APPLICATION

The relay monitor the battery and ensure that no leakage between battery and ground in DC systems.

PRINCIPLE OF OPERATION

The relay measures the leakage current between battery and earth if the current increased more than the set value the relay trips as per time delay setting . The relay output contacts are hand reset type. Relay operation without any fault current is determined by trip test facility.

TECHNICAL DATA

FEATURES

• Software based design

• Programmable time current characteristics

APPLICATION

The relay provides time graded phase and earth fault protection of Generators, Transformers, Feeder, capacitors etc.,

PRINCIPLE OF OPERATION

The relay measures the line current from each of the phases and if it exceeds the set threshold, then relay extends a trip signal after an operating time. The relay's operating time is determined by selecting one of the four inverse time characteristics. The relay has facility to active / inhibit the high set protection feature. The relay output contacts are self reset / Hand reset type. Relay operation without any fault current is determined by trip test facility.

TECHNICAL DATA

FEATURES

• Suitable for 1A / 5 A relay rating

• Choice of 6 IDMT curve and definite time

• History of 6 latest faults along with settings

• Self supervision facility

• Breaker status monitoring

• In-built breaker trip circuit supervision

• Disturbance records (DR) in IEEE COMTRADE format - Optional

• Event Records (ER) - Optional

• Programmable digital inputs and outputs

• MODBUS open protocol over RS - 485 port

• MODBUS protocol over RS - 232 port

• Draw out facility with inbuilt CT shorting

APPLICATION

The relay provides time graded phase, earth fault (2 stage) protection along with 5 shot auto re-closer and SCADA capability.

PRINCIPLE OF OPERATION

JNC 268 N / JNC 268 A / JNC 268 L :

The relay measures the line current from each of the line CTs and if the current exceeds the set threshold, then relay extends a trip signal after an operating time. The relay's "operating time" is determined by selecting "definite time" or one of the six "inverse time" characteristics.

A sensitive earth fault or restricted earth fault (suitable for high impedence REF scheme) is provided in the relay.

The input to sensitive earth fault protection can be connected in two ways. First one the residual current derived from three phase current transformers, and second is low output core balance current transformer can be connected. The input to restricted earth fault protection will be derived from neutral CT output with external stabilizing resistor.

The relay has facility to monitor circuit breaker operation through 52a or 52b aux contacts of circuit breaker.

4 programmable digital inputs (PDI) and 4 programmable digital outputs are provided and can be used to synthesize logic along with some internal digital inputs i.e.(phase OC pickup, Earth fault pickup, Phase high set trip, Earth fault OC trip, Earth fault high set trip,etc). Together, this feature can be effectively used to reduce the number of aux. tripping relays in a protection scheme. The trip relay (B1-B2) can be operated either when any one / more of the protection scheme provided inside JNC 268 x initiates the relay or any/more of the PDI initiates the same relay.

Each PDO has independent timer. Each PDI has programmable mask facility.

The relay in-built breaker trip circuit supervision and dedicated alarm contact to indicate trip circuit failure.

JNC 268 A:

Provides Multi shot auto re-closer facilitates automation of breaker operation. Auto re-closer can be programmed to pro­vide a maximum of five shots. "Dead time" starts when a trip signal is provided due to the occurrence of a fault involving L-L or L-G or L-L-G or L-L-L or L-L-L-G. After an elapse of a time interval equal to "dead time", closing command will be extended. The "reclaim time" timer starts at the instant when the "dead time" timer expires. If after extending the "breaker close" signal an over current fault was detected before the "reclaim time" timer reached its terminal count, then the relay understands that the fault in the system is still persisting and the over current relay will issue a trip signal. The relay tries to close the breaker for a maximum of the programmed number of shots before it choses to lockout. The relay can be configured for independent trip sequence as IDMT or Def. time

JNC 268 L:

The relay monitors line current even after the trip condition to ensure breaker operation. Even if small current exist in the line the relay sends trip command to adjacent or backup breaker after definite operating time. The current threshold and definite time required to detect breaker failure are programmable.

FEATURES

• Three phase over current and earth fault protection.

• Programmable operating characteristics

• Programmable auto reclosing facility.

• Independent trip sequence setting (IDMT / Def. time)

• Under voltage blocking for breaker close

• Trip counter.

• Fault zone indication.

• Breaker mal-operation indication.

• Auto / Manual control.

• Breaker status indication.

• Trivector meter to record energy and Load parameters.

• Ammeter and voltmeter with selector switch

• Separate cabinets for control unit and meter unit, which are mechanically fastened together

• Cabinet suitable for different types of pole mounting.

APPLICATION

Electrical Power for rural areas is supplied by 11 kV overhead lines. They are exposed to several faults like, lightning, heavy wind, fall of tree branches, fault created by animals / birds etc. When a fault occurs, the protection system trips the circuit breaker to prevent / minimize the damage. It is expected to locate the fault, clear and then restore the supply by reclosing the circuit breaker. It takes more time between power outage and restoration. More than 70% of the faults are observed to be temporary / transient in nature. Hence, power outage time can be reduced if the reclosing function is automated and carefully planned.

PRINCIPLE OF OPERATION

A circuit breaker whose tripping and reclosing functions are programmed and controlled automatically by an intelligent control unit is called as AUTO RECLOSER'. Auto Recloser can interrupt fault currents, and also programmed to reclose to restore the supply. The supply gets restored if the fault is of transient in nature. If the fault is of permanent type, the Auto Recloser tries to reclose the supply in two or three at­tempts (as set in the program) and finally goes to 'lock out' status, after which manual intervention is essen­tial.

The control unit is facilitated with manual control switches for circuit breaker trip and close operations. The circuit breaker status are indicated through indicating lamps. The operation of the circuit breaker is moni­tored by control unit after extending the trip / re-closing. The lockout contact will operate if breaker is mal-operated. The control unit has inbuilt trip counter which counts number of trips after installation. The count can be reset. The fault zone indicator is very useful only when several sectionalisers are used along the feeder. The zone numbers are based on time interval of closing the sectionaliser from the time of closing of auto recloser. The zone number will be displayed on the display. Zone number gives very useful informa­tion to locate the faulty section of the feeder quickly. Inbuilt power pack will generate sufficient DC power supply required to operate circuit breaker.

The lockout contact will operate on following conditions.

1. On permanent fault.

2. Breaker mal-operation

3. Very low voltage.

4. Trip when unit is manual mode

FEATURES

• Wide over current setting

• Fast reset time

• History of 5 latest faults

APPLICATION

JNC 154 is a numerical local breaker backup relay The relay is used to check the operation of feeder breaker and to trip all the breaker feeding fault in the event of feeder breaker fail to trip.

PRINCIPLE OF OPERATION

The relay is designed to trip the feeder end CB if the protective relay at the distribution end operates but its corresponding CB fails to operate. The current is derived from line CT. The instantaneous trip output contact operate when the over current exist and protective relay operated. The protective relay contact (PRC) input is required. The delayed output contact operates after selected definite time.

TECHNICAL DATA