Electronic Overload Relay

We are offering Numerical Over Flux Relay (jnf020).

Features
Programmable V/F ratio
History of 5 latest relay closing details

Application
JNF 020 Over flux relay is used in power systems in order to protect transformers and generators against insulation failure and core damage due to over heating under prolonged over fluxing condition. It protects the equipment against abnormal V/F ratios due to system disturbance which can occur during starting, load sheding and shut down conditions.

Principle Of Operation
Over fluxing of a transformer occurs when its flux density exceeds rated density, it is caused when its V/F ratio is greater than that which the manufacture deems it safe. This of course is the case when it is connected directly to the generator i.e, without benefit of an intervening circuitbreaker and the generators excitation system is energized while accelerating to operating speed JNF 020 monitors voltage & frequency ratio, when it exceeds the set value it indicates fault and the output relay operates after a set alarm time delay.

We are offering Numerical Unbalance Voltage Relay (JNV026).

APPLICATION

JNV 026 is a numerical unbalance voltage relay, with under voltage(UV), over voltage(OV) and Neutral snap which is used for three phase systems etc.,

PRINCIPLE OF OPERATION

JNV 026 measures and displays 3 phase voltages (R,Y,B phases). It calculates percentage of unbalance voltage and if it exceed the set unbalance voltage the relay operates after elapse of operating time. Under voltage fault will be detected when voltage on any phase is less than the set Under voltage limit the relay operates after elapse of under voltage operating time. Over voltage fault is detected when voltage on any phase is more than the set Over voltage limit the relay operates after elapse of over voltage operating time. Neutral snap will be detected when Neutral is disconnected.

TECHNICAL DATA

RATINGS
Rated voltage and Aux. supply	220V AC/ 110VAC
Frequency	50Hz

SETTINGS
Rated voltage (Vn)	220 to 250 V in steps of 10V ( for 220V rated)
	110 to 125V in steps of 5V ( for 110V rated)
Unbalance voltage	1 to 10% in steps of 1%
UBV time delay	0 - 300s in steps of Is
Under voltage	Vn -50V in steps of IV (for rated voltage 220V)
	Vn -25V in steps of IV (for rated voltage 110V)
UV time delay	0 - 300s in steps of Is
Over voltage	Vn +25V in steps of IV for rated voltage
	220V & 110V
OV time delay	0 - 300s in steps of Is
Active / Inhibit facilities	Active / Inhibit facilities for UV, OV, UBV

OVER LOAD RATINGS
Over load	2 times rated voltage continuously.

BURDEN
Aux. Supply	10VA max.
Voltage Input	0.1 VA max

 

We are offering Neutral Unbalance Current Relay (JRC122).

FEATURES

• Software based design

• Instantaneous/Definite time

• Insensitive to harmonics

• Wide setting ranges

• Trip test facility

APPLICATION

Neutral unbalance current protection of double star capacitor banks with floating neutral.

PRINCIPLE OF OPERATION

The sensing current is converted to voltage by an internal resistor and this voltage is fed to a harmonic network which is tuned to fundamental frequency The output of filter is fed to 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 performs the function of control and also gives output signals for relay and LED driver circuits. The operation of the relay is indicated by the glowing of a 'Red' LED,which has to be reset 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. When this push button is pressed,the output element of the relay is energized and its contacts close to energize trip and alarm circuits.

TECHNICAL DATA

RATINGS
Current rating ( In )	1A/5A
Aux. Supply	1) 20 to 60V DC
	2) 75V to 150V AC/DC
	3) 175 to 300V DC
	185 to 250V AC

SETTINGS
Setting range	2.5% to 80% of rated current in steps of 2.5%.
Instantaneous	Less than 40 milli seconds.
Definite time	0 to 25 seconds adjustable in steps of 0.1 second.
Rejection ratio of 3rd harmonic to	25 : 1 .The relay will not operate at third harmonic
fundamental frequency	currents up to 25 times the setting.

OVER LOAD RATINGS
AC current input	2 times Rated continuous
	20 times Rated for 3 sees.

 

We are offering numerical transformer differential relay (JND040).

FEATURES

• Biased current differential protection

• Fast differential Hi-set

• Dual slope characteristics

• Inbuilt CT Ratio correction factor

• Adjustable 2nd harmonic restraint

• Adjustable 5th harmonic blocking

• Inbuilt Vector group compensation.

• Two groups of settings

• History of 5 latest faults

APPLICATION

JND 040 is a two winding numerical transformer differential relay. The relay is used for protection of power transformer against hazardous internal faults.

PRINCIPLE OF OPERATION

JND 040 provides differential protection for power transformer. Relay measures the line current of each phase from each windings of transformer. Relay calculates differential current (Id) and restraining current (Ir) per phase. The differential characteristics define the operating and the restraining regions. The shape of the characteristics defined by Initial pickup (ik), SLOPE1 (DF1), SLOPE2 (DF2) and break point (kp) are programmable. If Tr' is less than 'kp' then characteristics is defined by 'DF1' and is applicable for small differential currents. If Tr' is greater than or equal to 'kp' then characteristics is defined by 'DF2' and is applicable for large differential currents. If the operating point i.e. (Id, Ir) is within the operating region then relay trips. The relay provides programmable 2nd and 5th harmonic current restraint, which, exist when transformer is energized and over excitation condition exists respectively. The relay provides stability on external "line to line" and "line to ground" faults. The relay has in-built vector group compensation selection and CT ratio correction hence the usage of external interposing CT can be avoided.

 

 

 

 

 

 

 

 

 

FEATURES

• Software based design

• Instantaneous/Definite time selection

• Wide setting range

• Wide auxiliary supply

APPLICATION

Earth fault protection in transformer generator motor and capacitor banks.

PRINCIPLE OF OPERATION

The sensing Voltage is applied to the input terminals of the relay. The applied voltage is amplified and fed to a Voltage Comparator. Output of the comparator is applied to the processor. The Program residing in the CPU performs the function of measurement and extends a trip signal after the set time delay is reached. The Relay contacts are self reset type and indications are latched, RESET button provided on the front of relay to clear these latched indications. TEST button is provided to test the relay contacts for trip and alarm circuits.

TECHNICAL DATA

RATINGS
Voltage rating	63.5V/110V AC
Auxiliary supply	l)20V to 60VDC
	2)75 V to 150V AC/DC
	3) 175V to 300V DC
	185V to 250V AC

SETTINGS
Voltage setting	2.5% to 80% in steps of 2.5%
Definite time	0.1 to 25sec in steps of 0.1 sec

OVER LOAD RATINGS
Voltage input	2 times Rated continuous

BURDEN
Voltage input	Less than 2VA at Rated
Auxiliary supply	Less than 2W (Non Operated)
	Less than 5W (Operated)

ACCURACY
Operating value	± 5%
Operating time	± 5% or ± 30msec
Instantaneous time	Less than 40msec.
Drop-off to pick up ratio	80% to 95%

 

FEATURES

• Software based design

• Programmable time current characteristics

• Choice of four curves

• Selectable characteristic angle

• Programmable directional / Non-directional element

• Draw - out case

APPLICATION

The relay provides time graded phase and earth fault protection of Parallel transformers, Transformer feeders, Parallel feeders, ring main system 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. Relay operation without any fault current is determined by trip test facility.

 

RATINGS
Current rating (In )	1A/5A
Rated Voltage	OVER CURRENT 110V AC
	EARTH FAULT 63.5V AC
Aux. Supply	1) 20 to 60V DC
	2) 75 to 150V AC/DC
	3) 175 to 300V DC
	185 to 250V AC

SETTINGS
Operating characteristics	1) 3.0s Normal Inverse
	2) 1.3 s Normal Inverse
	3) 1.5s Very Inverse
	4) 0.8s Extremely Inverse
Phase O/c (IDMT)	50 to 200% in steps of 10%
Earth fault (IDMT)	5 to 80% in steps of 5%
TMS (separate for O/c & E/F)	0.1 to 1.0 insteps of 0.01
Phase Hi-set	200 to 3200% in steps of 200%
Earth fault Hi-set	50 to 800% in steps of 50%