NC20 BANK CAPACITOR PROTECTION RELAY THE COMPREHENSIVE SOLUTION FOR CAPACITOR BANK PROTECTION
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Protection Relays BANK CAPACITOR PROTECTION RELAY THE COMPREHENSIVE SOLUTION FOR CAPACITOR BANK PROTECTION — Application The relay type NC20 provides protection of shunt capacitor banks and harmonic filter circuits. • The capacitor banks may have the following configurations: • Single Wye grounded. • Single Wye ungrounded (with a resistor on the output of the neutral unbalance voltage transformer in order to develop the appropriate input current for the unbalance protection). • Double Wye ungrounded. The capacitor banks may be: internally/externally fused or fuseless capacitor units. A suitable compensation method is provided to compensate the inherent unbalance neutral current Protection 37, 49 and 50/51 (RMS) are based on RMS value measurement of the three phase currents (fundamental and harmonics up to the 11th) - Protective & control functions NC20 52 METERING - I L1...I L3,I L1RMS...I L3RMS,I EC,I N,... - Oscillography - Events&Faults recorder Undervoltage Undercurrent Phase unbalance Neutral unbalance overcurrent with inherent unbalance compensation 49 Thermal image (for series reactor) 50/51 Fundamental frequency phase overcurrent 50/51(RMS) RMS phase overcurrent 50N/51N Computed residual overcurrent 59 Overvoltage BF Breaker Failure 74CT CTs monitoring 74TCS Trip Circuit Monitoring TD Discharge Timer Control functions COMMUNICATION - USB - Modbus RS485 - Modbus TCP/IP - IEC 870-5-103/DNP3

— Measuring inputs • Three phase current inputs and one unbalance neutral current input, with nominal currents independently selectable at 1 A or 5 A through DIP-switches. • Three phase voltage inputs with programmable nominal voltages within range 50...130 V (UR=100 V). The user interface comprises a membrane keyboard, a backlight LCD alphanumeric display and eight LEDs. The green ON LED indicates auxiliary power supply and self diagnostics, two LEDs are dedicated to the Start and Trip (yellow for Start, red for Trip) and five red LEDs are user assignable. According to the hardware...

— Self diagnostics All hardware and software functions are repeatedly checked and any anomalies reported via display messages, communication interfaces, LEDs and output relays. Anomalies may refer to: • Hw faults (auxiliary power supply, output relay coil interruptions, MMI board...). • Sw faults (boot and run time tests for data base, EEPROM memory checksum failure, data BUS,...). • Pilot wire faults (break or short in the wire). • Circuit breaker faults. NC20 provides metering values for voltages, phase and neutral currents, making them available for reading on a display or to...

SPECIF ICAT IONS INPUT CIRCUITS GENERAL — Mechanical data Mounting: flush, projecting, rack or separated operator panel Mass (flush mounting case) 2.0 kg — Insulation tests Reference standards High voltage test 50Hz Impulse voltage withstand (1.2/50 ms) Insulation resistance — Voltage dip and interruption Reference standards — EMC tests for interference immunity 1 MHz damped oscillatory wave Electrostatic discharge Fast transient burst (5/50 ns) Conducted radio-frequency fields Radiated radio-frequency fields High energy pulse Magnetic field 50 Hz Damped oscillatory wave Ring wave Conducted...

GENERAL SETTINGS — Rated values Relay nominal frequency (f n) Relay phase nominal current (In) Phase CTs nominal primary current (Inp) Relay unbalance nominal current (INn) Unbalance CT nominal primary current (INnp) Relay nominal voltage (Un) Line VT primary nominal voltage (Unp) Compensation current (IC) 0.01...0.50 I Nn Compensation angle (PhiC) 0...359 ° Automatic compensation enable ON/OFF — Binary input timers ON delay time (t IN1ON, t IN2ON) 0.00...100.0 s OFF delay time (t IN1OFF, t IN2OFF) 0.00...100.0 s Logic Active-ON/Active-OFF — Relay output timers Minimum pulse width (t TR)...

Dth> Element • 49 Trip threshold Dq (Dth>) 1.100...1.300 DqB • IE>inv within CLP (IECLP>inv) 0.100...10.00 In • IE>inv Operating time (t E>inv) 0.02...60.0 s Note - The 49 protection is based on maximum of the RMS value measurement of three phase currents (the computed RMS value takes into account the contribution of fundamental and harmonic up to eleventh order.) IE>> Element • IECLP >> Activation time (t ECLP>>) 0.00...100.0 s • IE>> Reset time delay (t E>> RES) 0.00...100.0 s Definite time • 50N/51N Second threshold definite time (IE>>def) 0.100...40.0 In • IE>>def within CLP (IECLP>>def...

• Thermal image DTheta-r • Phase displacement angle of INC with respect to IL1 (jNC) PhiNCr Selective block IN: • BLIN Max activation time for phase protections (t B-Iph) • Phase displacement angle of IN with respect to IL1 (jN) PhiNr • Binary inputs state IN1, IN2...INx 0.10...10.00 s K1...K6...K10 • BLIN Max activation time for ground protections (t B-IE ) • Output relays state • Fault cause info (operating phase) L1, L2, L3 0.10...10.00 s Selective block OUT: • BLOUT Dropout time delay for phase protections (t F-Iph) Digital Fault Recorder (Oscillography) — 0.00...1.00 s COMTRADE • BLOUT...

— Connection diagram example L1 L2 L3 A VOLTAGE INPUTS Supervision unit FLUSH MOUNTING CUTOUT FRONT PANEL MODULO 4 RELE’ + 8 INGRESSI DIGITALI 4 RELAYS + 8 BINARY INPUTS MODULE BINARY INPUTS OUTPUT RELAYS START TRIP