NG20 — synchronous generator protection relay
NG20 is a digital relay of the PRO-N family for protection of synchronous generators and non-self-starting synchronous motors. It includes phase overcurrent protection, frequency, voltage and current supervision, and loss of excitation protection. Parameters are set in ThyVisor software via a USB-B port.
- Object
- synchronous generators, non-self-starting synchronous motors
- Functions
- 50/51, 59N, 81, 51V, 50N/51N, 27, 59, 37P, 40, 46MG, 49MG, 55, 51LR(48)/14
- Option
- function 26, temperature via Pt100
- Communication
- USB-B, ThyVisor software
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
NG20 belongs to the digital relays of the PRO-N family and contains the functions required to protect synchronous generators or non-self-starting synchronous motors. The standard set of protection and control functions covers phase overcurrent protection, overfrequency protection and zero-sequence overvoltage protection. This is how the main machine parameters are monitored in operation. The relay can be set to generator mode or to non-self-starting synchronous motor mode, and the set of functions stays the same. The specification also lists functions 50/51, 59N, 81, 50N/51N, 27 and 59.
Overcurrent protection with voltage control or restraint (51V), together with zero-sequence current protection, covers short circuits in the generator and in the external network. The relay monitors the minimum and maximum values of voltage, frequency and current. Voltage control or restraint is needed so that the current protection can distinguish a short circuit from a permissible overload, while zero-sequence current protection acts on earth faults. Directional underpower protection (37P) detects the generator changing to motoring mode, and loss of excitation protection (40) operates when the machine loses excitation.
For the generator and the synchronous motor, negative-sequence current protection (46MG), a motor/generator thermal model (49MG), minimum power factor protection (55) and locked rotor protection (51LR(48)/14) are provided. The last is required for use with synchronous motors. Optionally the relay is supplied with extended hardware and software configurations, including thermal protection based on machine temperature measured by Pt100 sensors (function 26).
Configuration and monitoring are performed in ThyVisor software via a USB type B port. A leaflet, an order code table and a manual are available for the relay. It is installed on generators of small hydro, diesel and gas engine power plants, on standby and emergency generators of industrial facilities and on synchronous motors of compressors and pumps. For generators that need differential protection, out-of-step protection and 100 % stator protection, the XMR-D terminal of the XMORE platform is available.
Technical specifications
| Object | synchronous generators, non-self-starting synchronous motors |
|---|---|
| Functions | 50/51, 59N, 81, 51V, 50N/51N, 27, 59, 37P, 40, 46MG, 49MG, 55, 51LR(48)/14 |
| Option | function 26, temperature via Pt100 |
| Communication | USB-B, ThyVisor software |
Request a price and lead time
NG20 — synchronous generator protection relay. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
Which machines does the NG20 relay protect?
Synchronous generators and non-self-starting synchronous motors, including generators of small hydro, diesel and gas engine power plants and standby generators of industrial facilities.
Which NG20 protections cover loss of excitation and generator motoring?
Loss of excitation protection (40) and directional underpower protection (37P), which detects the generator changing to motoring mode.
How does NG20 monitor machine temperature?
Optionally with Pt100 sensors, which is function 26 within the extended hardware and software configurations.
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