Neutral grounding resistor(NGR),China

THT-ZT resistor inserted between neutral and ground of a transformer serves to limit fault current to a safe predetermined level

1. About us:

Baoding TIanwei Hengtong Electric company is a domestic professional manufacture of power system neutral earthing equipments and complete implements ISO9001 quality management system. We have a excellent sales performance all over the world and have been exported to more than 40 countries.

 

2. Principles:

THT-ZT Neutral Grounding Resistors are designed to provide added safety to industrial distribution systems by limiting ground fault current to reasonable levels. In a typical solidly grounded three phase system, the neutral is tied directly to earth ground. This can cause high ground fault current (typically 10,000 to 20,000 amps) and excessive damage to transformers, generators, motors, wiring, and associated equipment. Inserting an THT-ZT Neutral Grounding Resistor between neutral and ground limits fault current to a safe level (typically 25 to 400 amps) while still allowing sufficient current flow to operate fault clearing relays.

3. Service conditions:

3.1 Ambient temperature: -40°C~60°C

3.2 Altitude: less than 4000m

3.3 Relative humidity: less than 95% (25°C)

3.4 Rated frequency: 50/60HZ

3.5 Location: outdoor/indoor

 

 

4. Characteristics:

 

4.1Designed in strict accordance with IEEE Standard 32

 

4.2High efficiency of electric conductivity and high-temperature endurance nichrome resistor

 

4.3Corrosion resistant aluminized zinc steel,stainless steel,cold-roll steel enclosures.

 

4.4Corrosion resistant stainless steel A2-70 screws

 

4.4 LZZBJ9 resin casting insulation enhanced type current transformer

 

4.5 Hidden binding structure Air-cooling system

 

4.6 Sealed cubicle with highest protection level of IP55.

 

4.7 Intellect controlled unit realize the unattended operation  

 

4.8 Fully factory assembled - no field assembly required

 

4.9 A zigzag connecting grounding transformer is needed when the transformer windings adopt delta connection. 

 

5. Regular Technical Particulars for reference

Type	Rated Voltage(KV)	Short Time Current(A)	Flow Time (S)	Resistance Value(Ω)	Outer Dimensions(mm)
THT-ZT-6/34.64	6	100	10	34.64	1200x1200x1870
THT-ZT-6/17.32	6	200	10	17.32	1200x1200x1870
THT-ZT-6/8.66	6	400	10	8.66	1200x1200x1870
THT-ZT-6/5.77	6	600	10	5.77	1200x1200x1870
THT-ZT-10/14.43	10	400	10	14.43	1200x1200x1870
THT-ZT-10/9.62	10	600	10	9.62	1200x1200x1870
THT-ZT-10/7.22	10	800	10	7.22	1200x1200x1870
THT-ZT-10/5.77	10	1000	10	5.77	1200x1200x1870
THT-ZT-35/20.21	35	1000	10	20.21	2760x2600x2000
THT-ZT-35/10.10	35	2000	10	10.10	2760x2600x2000

Notes: manufactures various resistors according to the customer’s requirement, the design inaccuracy is ±3%, the flow time is various from 10s, 15s,30s, 60s,2h.

6. Information needed to quote: 

6.1System Voltage

6.2Line-to-Neutral Voltage

6.3Current Rating

6.4Maximum Time On

6.5Current Transformer Ratio, capacity (if applicable)

6.6Grounding Transformer KVA Rating, connection symbol and the transformation ratio (if applicable)

6.7Material of the enclosure:aluminized zinc steel,stainless steel or cold-roll steel

6.8IP protectional grade

6.9Color

6.10Installing place

6.11Line mode.

Neutral grounding resistor(NGR),China