Neutral Grounding Resistor

Neutral Grounding Resistors (NGRs) are used to limit the fault current and ensure safety of equipment and personnel in industrial systems.

Neutral Grounding Resistor systems can be inserted between the neutral and ground in a power system to provide ground fault protection through resistance. The fundamental purpose of a Neutral Grounding Resistor (NGR) is to limit ground fault currents to safe levels so that  sensitive and selective earth fault protection  relay can take place and  all the electrical equipment in a power system is protected. Neutral Grounding Resistors are also commonly referred to as Neutral Earthing Resistors and Earth Fault Protection Resistors

• Production Capacity: 25 Nos./Month
• Delivery Time: 8 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

Neutral Grounding Resistors (NGRs) are used to limit the fault current and ensure safety of equipment and personnel in industrial systems.

Neutral Grounding Resistor systems can be inserted between the neutral and ground in a power system to provide ground fault protection through resistance. The fundamental purpose of a Neutral Grounding Resistor (NGR) is to limit ground fault currents to safe levels so that  sensitive and selective earth fault protection  relay can take place and  all the electrical equipment in a power system is protected. Neutral Grounding Resistors are also commonly referred to as Neutral Earthing Resistors and Earth Fault Protection Resistors

• Production Capacity: 25 Nos./Month
• Delivery Time: 8 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

NGR & VC Panel normally consist of two separate cubicles attached to each other. The Resistance cubicle consists of number of Resistance Banks (Tiers) mounted one on top other and supported on HT Insulators. The enclosure is fitted with covers, provided with louvers and wiremesh. A Space Heater is provided to prevent condensation of moisture.

This Type of system is used for Parallel operating Generators in which all VC's are interlocked with each other and at a time only one VC is connected to NGR. In such system one comman NGR is used for multiple Generators. 

The NIS Cubicle houses the Isolating Switch (Vacuum Contactor) and CTs, as desired.LT Terminal Box for housing Thermostat and MCB, ON / OFF indicating lamps & LT terminals of Isolator & CTs etc. are provided in the NIS Cubicle.

• Production Capacity: 25 Nos./Month
• Delivery Time: 8 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

NGR Element Material:

• Formed Stainless Steel Grid  is one of the Type of construction of Resistor Element. This Type of Resistor elements are used in generally in cement Industy Industry and High current application.

Advantages of This Type Elements:

• High mechanical strength 
• Good ability to absorb mechanical vibrations
• Resistor element to element welded connections
• Economical construction

Resistor Element:

• Material used for this type of construction are AISI-304, AISI-410 & AISI -406 

NGR Enclosure Material:

• Enclosure will be provided in MS (CRCA), Aluminium, Unpainted Stainless Steel (AISI-304/316), painted Stainless Steel (AISI-304/316), Hot Dip Galvanised, Normal Galvanising as per customer requirement and thickness of enclosure will be 1.5mm -3 mm as per customer requirement

Diameter Available: 4 to 12 mm

• Production Capacity: 25 Nos./Month
• Delivery Time: 5 / 6 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

In outdoor distribution station there are many possibilities of damage to the neutral grounding connections due to various environmental effects causing open circuit or burning of NGR. This is a very dangerous continuity i.e. totally floating type. This may also result in failure of earth-leakage protection operating through neutral CT as the leakage current may not be able to flow through open circuit of neutral grounding connection.To prevent this type of failure, Fail Safe Relays must be installed. The fail safe relay will continuously monitor the continuity of NGR and neutral grounding connections and will trip the feeder circuit breaker as and when any open circuit occurs in neutral grounding connection or in NGR. The fail safe relay will ensure fail safe operation of neutral grounding system.This Type of system is generally used in Mines & Oil IndustryFor Mines, as per DGMS Guidelines, for MV System (3.3kV, 6.6kV & 11kV) Fault current is restricted to 50A and for LT system (415V & 230V) fault current is resyricted to 0.750mA

Price Range: 90000 to 450000

• Production Capacity: 25 Nos./Month
• Delivery Time: 8 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing

NGR & NIS Panel normally consist of two separate cubicles attached to each other. The Resistance cubicle consists of number of Resistance Banks (Tiers) mounted one on top other and supported on HT Insulators. The enclosure is fitted with covers, provided with louvers and wiremesh. A Space Heater is provided to prevent condensation of moisture.

A Single Pole Isolator is provided in the Neutral Circuit and the other end is connected to the NGR. The HT Bushings, to connect the NGR Terminals are mounted on the partition wall of the NGR & NIS Cubicles.LT Terminal Box for housing Thermostat and MCB, ON / OFF indicating lamps & LT terminals of Isolator & CTs etc. are provided in the NIS Cubicle.

• Production Capacity: 25 Nos./Month
• Delivery Time: 5 / 6 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

NGR Element Material:

• Stainless Steel Wire Grid  is one of the Type of construction of Resistor Element. This Type of Resistor elements are used in generally in NGR which is having small current rating i.e upto100A.

Advantages of This Type Element:

• Economical solution for low current ratings 
• Resistor element is a continuous without breakage

Material used for this type of construction are AISI-304,  AISI -406, Ni-Cr (80-20%)

NGR Enclosure  Material:

• Enclosure will be provided in MS (CRCA), Aluminium, Unpainted Stainless Steel (AISI-304/316), painted Stainless Steel (AISI-304/316), Hot Dip Galvanised, Normal Galvanising as per customer requirement and thickness of enclosure will be 1.5mm -3 mm as per customer requirement

Diameter Available: 4 to 12 mm

Industry:

• Cement Industry, Steel Industry, Power plants, substations, Metro, Transformer, Generators

• Production Capacity: 25 Nos./Month
• Delivery Time: 5 / 6 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

NGR Element Material:

• Punched Stainless Steel Grid  is one of the Type of construction of Resistor Element. This Type of Resistor elements are used in generally in Oil Industry, BHEL, NTPC, Adani, EIL etc

Advantages of This Type Elements:

• Better cooling due to large surface area
• Element to Element Bolted Connections
• Easy Replacement of Elements
• Suitable for continuous rating applications

Resistor Element:

• Material used for this type of construction are AISI-304, AISI-430 

NGR Enclosure Material:

• Enclosure will be provided in MS (CRCA), Aluminium, Unpainted Stainless Steel (AISI-304/316), painted Stainless Steel (AISI-304/316), Hot Dip Galvanised, Normal Galvanising as per customer requirement and thciness of enclosure will be 1.5mm -3 mm as per customer requirement

Thickness Available: 0.5 to 2 mm

• Production Capacity: 25 Nos./Month
• Delivery Time: 6 / 8 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

NGR Element Material:

• Patti  Grid  is one of the Type of construction of Resistor Element. This Type of Resistor elements are used in generally in NGR which is having  High current rating i.e. 800A-1500A

Advantages of This Type Elements:

• Suitable for Higher currents & Large time rating
• Cooling is achieved better in this type of construction.

Resistor Element:

• AISI-304,  AISI -430, Fe-Cr-Al (AISI-406)

NGR Enclosure Material:

• Enclosure will be provided in MS (CRCA), Aluminium, Unpainted Stainless Steel (AISI-304/316), painted Stainless Steel (AISI-304/316), Hot Dip Galvanised, Normal Galvanising as per customer requirement and thickness of enclosure will be 1.5mm -3 mm as per customer requirement

• Production Capacity: 25 Nos./Month
• Delivery Time: 5 / 6 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

NGR Element Material:

• Cast Iron Grid  is one of the Type of construction of Resistor Element. This Type of Resistor elements are used in generally in NGR which is having very Hight  current rating i.e. 2000-3000A 

Advantages of This Type Elements:

• Suitable for higher currents
• Resistor element is a continues without breakage

Resistor Element - Cast Iron
NGR Enclosure Material:

• Enclosure will be provided in MS (CRCA), Aluminium, Unpainted Stainless Steel (AISI-304/316), painted Stainless Steel (AISI-304/316), Hot Dip Galvanised, Normal Galvanising as per customer requirement and thickness of enclosure will be 1.5mm -3 mm as per customer requirement

Thickness Available: 12 mm to 22 mm

• Production Capacity: 25 Nos./Month
• Delivery Time: 5 / 6 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

Where continuity of service is a high priority, high-resistance grounding can add the safety of a grounded system while minimizing the risk of service interruptions due to grounds. The concept is a simple one: provide a path for ground current via a resistance that limits the current magnitude, and monitor to determine when an abnormal condition exists. This provides for maximum continuity of service, because no tripping occurs for the resistance limited ground fault.The ground current path is provided at the point where the service begins, by placing resistance in the connection from system neutral to ground. Control equipment continuously measures ground current; a relay detects when the current exceeds a predetermined level. An alarm alerts building personnel that a ground exists. The system has built-in fault tracing means to assist in finding the source of the ground. An integral transformer provides control power from the primary source.The pulser circuit offers a convenient means to locate the faulted feeder and trace the fault to its origin. The pulser is available any time a fault has been detected. The pulse intervals are controlled by an adjustable recycle timer. The “pulse” light flashes on and off, corresponding to the on-off cyclesof the pulser contactor. The pulser contactor switches a bank of resistors on and off, thus allowing a momentary increase in the ground current (approximately a 5 A current pulse above the ground current).The current pulses can be noted with a clamp-on ammeter when the ammeter is placed around the cables or conduit feeding the fault. The operator tests each conduit or set of cables until thepulsing current is noted. By moving the ammeter along the conduit, or checking the conduit periodically along its length, the fault can be traced to its origin. The fault may be located at the point where the pulsing current drops off or stops.

• Production Capacity: 25 Nos./Month
• Delivery Time: 8 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

This Type of Eathing system is used when High Resistance grounding is required. This type of NGR is mostly used in Generator Earthing. Fault Current rating of such system is 5-10A.

This type of system is used where continuous operation is required though falut is occured. 

In this system, a single phase distribution transformer is used in conjunction with a loading resistor, to provide high resistance grounding.

It allows the system to operate like an ungrounded system under normal operating conditions, while still retaining the ability to limit fault currents during a fault conditions. 

The primary of the transformer is connected from the system neutral to ground. The loading resistor is connected across the transformer secondary.When a ground fault occurs downstream of the grounding transformer, ground fault current flows through the fault, back through ground to the grounding transformer.The loading resistor limits the current flow in the secondary winding, which in turn limits the flow of the ground fault current upto 5A to 10A back into the system through the primary of the grounding transformer as per customer requirement. Value of Loading Resistor in Secondary circuit is calculted on the basis of how much fault current is required & system voltage.

The transformer primary voltage rating should be the same as the system line-to-line voltage or  line-to-Neutral voltage. The secondary voltage is normally 240 or 110 volts.

• Production Capacity: 25 Nos./Month
• Delivery Time: 5 / 6 weeks from Manufacturing clearance
• Packaging Details: Indian Roadworthy packing / Export seaworthy Packing

Neutral Earthing Resistor (NER) is used to restrict the flow of current during an earth fault on an alternate current distribution system. The resistor is connected between the neural point of a transformer and earth or generator and earth. The neutral earthing resistors (NER) offer dependable protection every time whenever there is a fault. Neutral earthing Resistor (NER) are used in power distribution, mining and industrial installations etc. The resistor is designed to tolerate most hazardous work conditions and atmospheric changes. Neutral Earthing Resistor (NER) is known for durability and reliability.

 

Highlights:

• Resistance value pre-determined to operate fault-clearing relays and to prevent damages
• System is designed as per to current and time ratings and compatible with the protection switch gear
• Resistance value is precise and determined and remains constant throughout life
• Made from tough steel grids of a high quality iron-chrome-aluminium
• Non-corroding and offer good stability
• Mica and ceramic insulators
• Resistor in fully protected and ventilated steel enclosures