The ngr series's neutral site-to-place electrical counters apply to the 3-66 kv cable-based urban distribution grid, the distribution grid of major power users, such as major industrial and industrial enterprises, airports, ports, metros, and power systems for generators and plants, which are protective appliances used to connect transformers or generators to the ground。
The product electrical resistance component uses *nickel chromium alloy electro-thermal metal material, which has characteristics such as high temperature resistance, high oxidation resistance, high tensile resistance, high electrical resistance and stable resistance values, especially if it is still able to maintain good electro-thermal metal performance at a high temperature of 1000°c, with the product operating safely and reliable。
Depending on the mode of connection or customer demand, epoxy resin can be configured as a dry ground transformer, a zero sequence electrical current sensor, a single separation switch, an electrical resistor online monitoring device, a heater and a temperature-moisture controller。
Product characteristics
The neutral point-to-ground resistance element of the ngr series is made of resistance, special formulation stainless steel alloys, the main performance characteristics of which are:
(b) high temperature tolerance: a melting point (1375-1500°c) and a high temperature of 1000°c
High tensile strength: the tensile strength of 700 mpa remained essentially constant at 900 - 1000°c;
(b) high resistance rate: 1. 25 m. M, which reduces the size of the resistance element
(a) resistance stability: a resistance temperature factor of 1. 05 х10-4 times/°c, with very small variations in resistance values at high temperatures, contributing to the sensitivity of protection
Strong oxidation resistance: good oxidation resistance at temperatures around 1000°c. Suitability to highly polluted environments;
(b) resilientness: remain robust and non-fragile under operating conditions of severe temperature change
(a) full of types: multiple structural types of resistance elements, such as bands, grids, spiral wires, ribs, smooth wires, etc., according to the size of flow capacity
Modularization of electrical resistance elements: each type of electrical resistance system produces standard elements with multiple specifications to achieve modularization. (a) by means of a stringed and combined approach, it is possible to combine any combination to accommodate your requirements for various parameters, such as flow capacity, voltage, resistance values, etc., and to replace them
(a) good dissipation design: the cabinet is well-structured with cooling gas flow routes, the dissipation function is good and local hot spots and burning points are eliminated
Long useful life: 30 years of commitment. Client visits revealed that in the electrical restraint cabinets in service, more than 50 years had elapsed。
Implementation standards
Dl/t780-2001 zero-point ground resistor in the distribution system
Gb6450 dry electric transformer
Dl/t620-1997 ground-over voltage protection and insulation of communication electrical devices
Gb/t16927-1997 high voltage test technology
Gb1208-1997 electric current sensor
Gb4208-1993 shell protection level (ip code)
Ieee32-1972 technology, terminology and testing of neutral point-to-ground devices
Gb311. 1-1997 insulation of high pressure transmission and distribution equipment
Dl/t593-1996 technical guidelines for shared ordering of high pressure switches
Gb/t1102-1999 test criteria for the handover of engineering electrical equipment for installation of electrical installations
Other relevant and electrical industry standards
Conditions of application
Peripheral air temperature: upper limit + 50°c, lower limit -35°c
Altitude: normally not exceeding 1,000 m
Wind pressure: not greater than 700 mpa (equivalent to 34 m/s)
Seismic intensity: not greater than 8
Landscape thickness: not greater than 15 mm
Air pollution level: not greater than iv
Model and meaning
N g r - □ - □
Quite a bit
Zero, zero, zero, zero
│ └ - - system rated voltage
│ ─ electrical resistor
- nexting
Neutral - neutral