Neutral-To-Earth Connection
The resistor connects the system neutral to the earthing grid. Resistance, short-time current and duration are specified together to match the earth-fault duty of the installation.
GreenPower
GP-NER-20kVNeutral Earthing Resistor Cabinet
System Rated Voltage20 kV
Short-Time Current150 A / 10 s
Nominal Resistance77 Ω ±5%
Enclosure ProtectionIP54, outdoor
Product Overview
GP-NER-20kV is a custom outdoor cabinet for resistance earthing of 20 kV system neutrals. The configuration shown uses a 77 Ω ±5% resistor with a 150 A, 10 s short-time rating to limit earth-fault current. An LZZBJ9-10 current transformer provides a 150/1 A measurement signal. The resistor and CT are housed in an IP54 steel enclosure with front and rear access.
Current Measurement
The wiring drawing specifies a 150/1 A CT with accuracy class 1.0 and a 15 VA burden. Its secondary signal is brought to the XT1 terminal block for the external measurement circuit.
Key Features
Outdoor IP54 Enclosure
The cabinet uses 2 mm cold-rolled steel plate, finished in RAL7035, with a rain canopy for outdoor installation.
Front And Rear Access
Front and rear doors provide access to the resistor assembly and connections. The drawing specifies reinforced panels and ventilation openings lined with dust-proof mesh.
Bottom Cable Entry
Primary, earthing and secondary cables enter from below. Rubber rings and cable clamps are provided at the cable openings shown in the base plan.
Technical Specifications
| Parameter | Data |
|---|---|
| System Rated Voltage | 20 kV |
| Short-Time Current | 150 A |
| Duration Of Short-Time Current | 10 s |
| Nominal Resistance | 77 Ω |
| Resistance Tolerance | ±5% |
| Current Transformer Model | LZZBJ9-10 |
| Current Transformer Ratio | 150/1 A |
| CT Accuracy Class | 1.0 |
| CT Rated Burden | 15 VA |
| CT Rated Frequency | 50 Hz |
| Installation | Outdoor |
| Enclosure Protection | IP54 |
| Cabinet Dimensions (W × D × H) | 1300 × 1450 × 2000 mm |
| Cabinet Material | 2 mm cold-rolled steel plate |
| Cabinet Colour | RAL7035 |
| Base | No. 10 channel steel |
These values describe the 20 kV, 150 A / 10 s configuration in the catalog outline and wiring drawings. Resistance, current, duration and enclosure requirements are confirmed for each order.
Installation And Connections
Foundation And Earthing
The cabinet measures 1300 × 1450 × 2000 mm (W × D × H). Its channel-steel base has copper earthing blocks on both sides with M12 threaded holes. Confirm the foundation, anchor positions and bottom cable openings against the supplied base plan.
Resistor And CT Connections
The primary diagram shows the resistor and CT in the neutral-to-earth circuit. CT-S1 and CT-S2 connect to XT1-1 and XT1-2 respectively. The outline drawing identifies the neutral-point connection, earthing connection and secondary terminal locations.
The manual includes cabinet views, internal arrangements, the base plan and wiring diagrams. Use the supplied assembly drawings to confirm the foundation, cable openings and terminal connections.
Service Conditions
Altitude
Not exceeding 4000 m above sea level.
Ambient Temperature
-40°C to +60°C.
Relative Humidity
Not exceeding 95% at 25°C.
Power Frequency
48-52 Hz for 50 Hz systems. The CT shown in this configuration is rated 50 Hz.
The installation site should be free from corrosive gases, steam and explosive dust. State any special operating conditions or other frequency requirements with the enquiry.
Configuration And Ordering
System And CT Requirements
Provide the system voltage, neutral arrangement, required earth-fault current, resistance and short-time duration. Define the CT ratio, accuracy class, burden and external circuit requirements. Systems without an accessible neutral may require an earthing transformer as part of the earthing scheme.
Cabinet And Monitoring Options
Confirm the enclosure material, protection level, installation location and cable entry arrangement. Specify any isolating switch, earth-fault event recording, temperature and humidity control, or monitoring interface required for the ordered assembly.
Specify Your GP-NER-20kV Cabinet
Send the system voltage, required earth-fault current, resistance and duration. Include the neutral arrangement, CT requirements and installation details for your project.