Voltage Relays. Ensuring Reliable Protection for Electrical Systems against Voltage Faults. ISO 9001:2008 Certified.

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Annabella French
5 years ago
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1 Ensuring Reliable Protection for Electrical Systems against Voltage Faults Voltage Relays Inside the Catalogue Range Model Selection Specifications Technical Terms & Data ISO 9001:2008 Certified Delivering Value

Introduction M-Kris Electric is an emerging company in electrical sector committed to provide quality and reliable products and solutions to its customers for improving the performance and

2 Introduction M-Kris Electric is an emerging company in electrical sector committed to provide quality and reliable products and solutions to its customers for improving the performance and reliability of their electrical systems. The current range of M-Kris Electric includes digital metering devices in single and multifunction versions (V, I, f, pf, kw, kwh, Harmonics, THD ), protection relays (earth leakage, earth fault, under/ over voltage, under/over frequency, over-current, phase monitoring, reverse power...), current and instrument transformers. Electronic Overcurrent Relays Voltage Relays Electronic and electrical devices are designed to operate at a certain voltage range and the device is likely to get damaged if the voltage is above or below that range. Under voltage is the decrease in AC RMS voltage at power frequency to less than 90% of the rated voltage whereas over voltage is the increase in +10% range of the rated voltage. Under voltage may cause the device to stop working or it may cause damage to motors if it is excessive. Due to over voltage electrical devices may stop working, or may even burst into flames. Phase reversal is the condition in which two of the three phases (RYB) of supply line reverses. Switching any two of the three phases will cause the motor to turn in wrong direction which may cause major collateral damage. Single phasing is a condition in three-phase supply in which supply to one of the phase is cut-off. It is caused by single phase protection devices such as fuses and circuit breakers. It may cause excessive noise and vibration in motor. Principle of Operation In voltage relay, the true RMS voltage, phase sequence (in 3-phase model) and single phasing (in 3-phase model) is continuously monitored through the microcontroller and the measured voltage, phase sequence, single phasing, and phase unbalance is continuously monitored against the threshold voltage (i.e. the set value for the under voltage and over voltage), phase failure and single phasing and as soon as the fault is detected by microcontroller, the relay trips and mains supply is disconnected and hence the devices are protected against the under voltage, over voltage, phase reversal, phase failure and phase unbalance. User benefits: True RMS sensing (Microcontroller based design) Wide range to choose from 110/220/415/550 VAC and 24/48/110/220VDC Single and Three phase options (for ac version) UV and OV thresholds settable by user Separate LEDs for UV, OV, Single Phasing and Phase Reversal faults Last fault memory for UV, OV, Single Phasing, Phase Reversal and Phase Unbalance Wide range of aux. supply - 110V/220V/415V/550V AC or 24VDC or universal supply VAC/DC

3 Selection Chart NOTE :- Customized versions are also available on demand Dimensions (in mm) Front view Rear view

4 Wiring Diagrams Menu - for setting Parameters 1. Over-voltage (OVEr) protection setting : Ranges from 430V to 480V 2. Under-voltage (UV) protection setting : Ranges from 260V to 400V 3. Single Phase (SPH) protection setting : Enable/Disable (Optional) 4. Phase Reversal (rev) protection setting : Enable/Disable (Optional) 5. Phase Unbalance (Un) protection setting : Ranges from 2% to 50% 6. Trip time delay (del) setting : Ranges from 0 to 30 seconds (common for all type of faults) 7. Password : 4 digit password (factory set) NOTE :- Menu settings may vary (in sequence & ranges) in customized versions.

5 Specifications Parameter System Aux. Supply Threshold Setting (UV) Threshold Setting (OV) Relay output Accuracy Parameter Value for Voltage Relay 1 phase 2 wire / 3 Phase 4 Wire / 3 Phase 3 Wire 415 /230 / 110 VAC, 50/60 Hz (-20%, +15%), Universal VAC/DC 70-85% of rated voltage % of rated voltage Single changeover contact 5A at 240VAC Voltage: 1% / 0.5% of full scale Temperature -20 C to + 55 C Humidity Weight Dimensions Panel Cut out Mounting < 95% RH (non condensing) 350 g 96 x 96mm, depth 65mm 92 x 92 mm Flush Mounting (clamps provided) Glossary of Terms and Faults Over-Voltage Protection Over-voltage situations normally arise when the grid is not loaded fully (usually happens at night or in winter). Over-voltages result in increase in current, poor power factor and stress on the insulation of the cables. Sensitive equipment particularly electronic loads are more susceptible to damage from overvoltage conditions. User can set over-voltage value along with the appropriate time delay to ensure tripping of the relay in case of over-voltage. Under-Voltage Protection Under-voltage conditions are very common due to excessive load on the grid supply and results in the overloading of the motor due to compensatory increase in current. Though overload tripping comes into play in case of under-voltage, a separate under-voltage setting is recommended, and hence provided with a time delay for tripping.

6 Glossary Contd. :- Single Phasing Protection Like overload, single phasing is a very common fault occurring in electrical systems which may happen due to the disconnection of a phase - likely causes are poor termination, faulty circuit breaker or contactor, cable break. A running motor will tend to draw more current in event of single phasing trying to maintain the load from two available phases. This may result in burning of the windings. Phase Unbalance Protection Though more common in single phase loads connected on 3 phase systems, the phase unbalance i.e. the voltages/currents are not equal in all three phases (R-Y, Y-B, R-B), results in unequal loading of the three phase motor and may result in humming/noise from the motor. If unchecked, the motor windings may be damaged. Phase Sequence Reversal Protection The sequence of the phases (RYB) plays a very important role in determining the rotation direction of the motor. For the phase sequence of RYB, the motor rotates in a particular direction due to the corresponding direction of rotating magnetic field. Normally phase reversal condition may arise due to wrong connections (interchange of any two phases) during maintenance or repairs of the installation. Phase reversal is especially dangerous, when the motor is installed in applications such as cranes, lifts, escalators or threading mills. Though highly unlikely, if phase reversal happens while motor is operating, it will damage the motor (and connected load) extensively. Hence phase reversal monitoring is essential during the startup of all the 3 phase motor installations and for some installations, it may be required for entire run duration. Earth Leakage Relays Digital Panel Meters Power Analysers Phase Monitoring Relays Process Indicators Motor Protection Relays M-Kris Electric 305, DDA Pocket-1, Sec-23, Dwarka, New Delhi INDIA Phone: Whatsapp: info@mkris.com Web: Specifications subject to revision without prior notice. ver1.5

Technical Datasheet. True RMS Digital Protection Relay. Line Monitoring Relay

Technical Datasheet. True RMS Digital Protection Relay. Line Monitoring Relay Technical Datasheet RELAY-1 RELAY-2 k V Hz RESET ABH TEST True RMS Measurement True RMS Digital Protection V/Hz is used to protect against Over Voltage, Under Voltage, Phase Unbalance, Phase Sequence detection,