NC20

NC20 Capacitor Bank Protection Relay


The NC20 protection relay can be used to protect shunt capacitor banks and harmonic filter circuits. The capacitor banks can have the following configuration:

  • 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.The protections are equipped with a system for compensating inherent unbalance neutral current
  • Protections 37, 49, and 50/51 (RMS) are based on the measurement of the true RMS value of the three phase currents (fundamental and harmonics up to the11th). 

Features of the NC20 Capacitor Bank Protection Relay


Among the functions of the Thytronic NC20 relay, we find the monitoring of under voltage and under current, along with the control of the negative sequence overcurrent r, phase overcurrent, and maximum residual overcurrent, in addition to the supervision of overvoltage and detection of breaker failure.

The relay is capable of monitoring the phase current transformers and supervising the trip circuit to ensure reliable operation. Additionally, it optionally offers a hardware (HW PACK) and software (SW PACK) package for advanced configurations.
Regarding communication functions, it is equipped with a type B USB port for easy connection to the ThyVisor configuration software.

FUNCTIONS


STANDARD PROTECTIVE & CONTROL ELEMENTS

  • Under Voltage - 27
  • Under Current - 37
  • Negative sequence overcurrent - 46LT
  • Phase overcurrent side H and side L - 50/51
  • Maximum Residual Overcurrent - 50N/51N(1)
  • Overvoltage - 59
  • Breaker Failure - BF
  • CT Supervision - 74CT
  • Trip Circuit Supervision - 74TCS
  • Neutral unbalance current - 46N
  • Second Harmonic Restraint
  • Sequence of Fault Recorder (SFR)
  • Sequence of event Recorder (SER)

SW PACK OPTIONAL CONFIGURATION

  • Digital Fault Recorder (DFR)
HW PACK OPTIONAL CONFIGURATION
  • Thermal with Pt100 Probes - 26

COMMUNICATION FUNCTIONS

  • One USB Type B local port for communication with ThyVisor setup software

DOWNLOADS

NC20 Manual
Flyer NC20
NC20 Coding
PRO-N NC20 IEC 61850 Certificate

RELATED PRODUCTS

NC020

In recent years, the portion of the total load that produces harmonics has steadily increased due to the massive use of power electronics at all voltage levels. Thyristor converters, frequency converters, switching thyristors, and static compensators, such as Thyristor-Controlled Reactors (TCR) and Thyristor-Switched Capacitors (TSC), are commonly adopted in industrial applications and electrical utilities.


Capacitor bank filters consist of capacitor batteries and an air core connected in series, whose task is to absorb the harmonic currents generated by loads and all the above-mentioned power electronic devices. The purpose of the NC020 protection relay is to provide reliable protection for such an application, ensuring the system's safety.

Features of the NC020 Capacitor Bank Protection Relay


The Thytronic NC020 protection relay is designed to ensure reliable protection for capacitor banks. Its key functions include detection of breaker failure, monitoring of negative sequence overcurrent of the transformer, and control of the maximum voltage and phase current. This relay supports the Modbus RTU RS232 communication protocol.

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