Neutral grounding resistors


Product overview

Farady has own R & D team with outstanding technology and sophisticated equipment, advanced technology introduction and digestion of foreign countries, long-term commitment to the production of neutral grounding technology product research and development; to reduce the overvoltage and improve the safety and reliability of the network.

Farady import special stainless steel alloy materials, development and production of a series of neutral grounding resistors of the stainless steel cabinet, for 6 ~ 35kV AC network. In the system of cable power supply, the grounding capacitance current is larger. When the current is greater than the specified value will be generated when the arc grounding overvoltage. Injection of resistive current of the neutral grounding resistors mode is to give the point of failure, the fault current is resistive and capacitive properties, reduce the phase difference and voltage, reduce the fault current zero arc after the resignation rate, the overvoltage is limited within 2.6 times the phase voltage, improve the sensitivity function the relay protection on the trip, in order to effectively protect the normal operation of the system.

In the 6 ~ 35kV alternating current network, especially in the network with the cable power supply, the resistance grounding is widely used. However, if the transformer winding is delta connection, neutral point grounding grid, earthing transformer must be installed, and a resistor is arranged between the earthing transformer neutral point and the ground.

FL-NGR transformer neutral grounding resistor cabinet is a farady with complete sets of equipment including earthing transformer, the development requirements of these systems can be installed in the power plant power system, substation power supply system, industrial and mining enterprises in the distribution system, the realization of these grid uses in point via neutral grounding resistor system.

1, Altitude: no more than 4000m

2, ambient temperature: -40 to +60 degrees

3, relative humidity: no more than 95% (25 degrees C)

4, the installation place: air does not contain chemical corrosion of gas and steam, no explosive dust

5, power grid frequency: 48 ~ 52Hz (50 Hz system), 58 ~ 62 Hz (60 Hz system)

6, applicable to: Indoor & Outdoor

7, resistance installation point: the normal state of the neutral point displacement does not exceed 3% of the running phase voltage

Note: special conditions of use, please enquiry Farady tech dept during ordering  

1, targeted, protection in place

FL-NGR transformer neutral grounding resistors cabinet is suitable for the system neutral point using small resistance or neutral grounding of the occasion. At this point, the power grid has a single phase to ground fault, the need for immediate trip to remove the fault line. When a single-phase grounding occurs in the power grid, the grounding resistance provides additional resistance current to the ground, which causes the grounding current to be in a resistance capacity, thereby ensuring that the overvoltage is not more than 2.6 times the phase voltage.

2, compact structure, easy to install

FL-NGR transformer neutral grounding resistor cabinet Z scattered earthing transformer (such as system without neutral point is needed), resistor, current transformer, measuring instrument, grounding protection output terminals and other electrical equipment integrated in a closed metal cabinet, but also to selection of isolating switch, lightning arrester, complete delivery, high safety and reliability, layout clear and tidy, convenient installation and debugging and maintenance.

3, material selection, fully guarantee the quality of products

FL-NGR transformer neutral point earthing transformer resistance cabinet for high-quality dry-type transformer, the primary winding is “ZN” shaped stainless steel resistor wire; nickel chromium alloy (Cr20Ni80) material, its high conductivity, flow ability, high temperature, maximum use temperature can reach 1600 DEG; low temperature coefficient less than -0.045% / C, resistance stability, corrosion resistance, anti explosion, high reliability. Resistance alloy material used in all resistance unit is welded into a frame structure with multiple units using sub arc resistance unit adopts the high temperature resistant insulator (polymer) support connection. According to different customer requirements, our company can provide import resistor.

4, monitoring function is complete, and provide analog output

FL-NGR transformer neutral grounding resistor cabinet can be equipped with a current transformer and the normal action recorder, can monitor the unbalanced current in neutral point; single-phase ground fault, can record the action times; and to the protection and monitoring system provides analog output; can also according to need to install special lightning arrester.

5, strong technical force, and thoughtful service

Farady electric is a professional manufacturer, strong technical force, pre – technical exchanges and consultation can be in place at any time. After sales installation technical guidance can be carried out in a timely manner according to user requirements.

ModelSystem rating voltage(kV)Short time flow currentAShort time flow timeSRating resistance



P.S. We can design and manufacture all kinds of resistance according to user requirements, the resistance value from 1 ohm -2000, allowing the error of the current 1A-2000A. resistance value of + 3%. allows flow time 10s, 15s, 30s, 60s.

Overall size and installation

1, equipment installation wiring diagram as shown below


2, the resistance cabinet can be fixed on the concrete foundation, to maintain the resistance level. The equipment case should be grounded by the foot of the cabinet. The external dimension of the resistance cabinet is determined according to the specific parameters of the user. The following is the outline size of FL-NGR-6/400:


NGR cabinet overall size 1200L x 1200W x 1900H(mm)

Ordering instructions

Please advise the following parameters when ordering.

1 system rated voltage: (kV)

2 short term allowable current: (A)

3 nominal resistance value: (Ohm)

4 whether the installation of current transformer (CT): CT ratio and capacity, composite tolerance

6 incoming and outgoing type:above comer,buttom feeder,buttom incomer,buttom feeder,optional;

7 short time allowed flow time: (S)

The resistor cabinet material,

8 (IP) level of protection, color code and installation site;

9 do you need to install the ground record and temperature and humidity control device.


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Zhejiang Farady Electric Co.,Ltd




Add:NO.81,Sutai Road,Su’ao,Liushi,Yueqing,Zhejiang,China,325604