Maharashtra Electronic Industries

 
▪ Designed and tested as per IEEE -32 -1972 standards
▪ All stainless steel resistor elements and terminals
▪ All units triple insulated
NGR'S:
▪ Protects power system equipments against 50/60HZ faults (short circuit) and transient phenomena (lighting)
▪ Prevents additional faults from occuring
▪ Localises the fault
▪ Significantly improves system stability
▪ Provides safety to personnel
RANGE:
RATED CURRENT : 1AMPS TO 5000 AMPS.
RATED VOLTAGE : 380 VOLTS TO 33 KV.
RATED TIME : 10 SECONDS TO CONTINUOUS.
APPLICATION:
NGR'S are used in industrial power systems for resistance grounding of wye connected generators and transformers. NGR is connected between ground and neutral of transformers, generators and grounding transformers. NGR limits the fault current to a value enough to operate protective relays, thereby preventing unwanted damage to the system.
RESISTOR ELEMENTS
Are made of unbreakable corrosion proof jointless elements edge wound, coiled, formed, punched or tapered from stainless steel, CU-NI, NI-CR, Fechral or resistance material as per requirement.
CONSTRUCTION
Resistors grids are mounted on steel rods insulated by special heat resistant micanite paper tubes. Grid washers are of natural mica. Resistor grid assembly is mounted on angle iron structure properly supported to absorb vibration and stress during fault and transit. End connections of resistors is brought out to terminal box or through top or side mounted high voltage bushings. Stand-off/support insulators are ceramic or epoxy resin cast.
ENCLOSURE
Resistor grid assembly is housed in an enclosure made of heavy gauge sheet steel (≥ 2mm) totally enclosed, vermin proof, with screened or louvered covers (with fine wire mesh) on front and back for easy servicing. Bottom screening provided for maximum cooling of resistors. Corrosion resistant nameplate, clear warning labels (danger, high-voltage, earthing etc.) fixed on enclosure. Suitable earthing studs are provided on 2 sides.
Enclosures are designed for protection degree of resistors as per:
IEC 529, IS2147 (from IPOO to IP55).
Enclosure options:
All Aluminium, Stainless steel body.
Canopy to prevent standing steel body
Eyebolts in all four corners for easy handling/hosting.
Support stands for elevating above ground.
TERMINALS
Bushing type terminals for neutral and earthing connections are housed into a separate vermin proof, weather proof compartment. Epoxy insulated terminals are provided for terminating the specified size of cables, earthing strips and supplied with tinned copper lugs/strips. Connections between the equipment neutral and resistors is done by single core unarmoured cable of suitable size. Top or Side mounted bushings can also be provided as per requirements.
PAINTING
Power coated or epoxy painted as per specification. Synthetic enamel shade 632 as per IS-5