Low Voltage Neutral Grounding Resistor

Overview

In low-voltage systems such as the 0.66 kV power supply in coal enterprises, the 0.38 kV auxiliary power system in thermal power plants, and the 0.22 kV emergency power supply from low-voltage diesel generators, neutral grounding is a critical design measure to ensure safe and stable operation. Grounding fixes the neutral potential at 0 V, ensuring that the voltage between each phase and the neutral remains stable at the rated value (0.66 kV / 0.38 kV / 0.22 kV, approximately corresponding to 400 V / 230 V / 127 V in international standards), regardless of whether the three-phase load is balanced, thereby preventing equipment damage from overvoltage or failure to start due to undervoltage. From a safety perspective, if a phase line insulation fault occurs, neutral grounding forms a “phase—ground—neutral” loop, generating high current to trigger protective devices, which prevents electric shock to personnel (e.g., in underground coal mines), avoids fault escalation in power units (e.g., thermal plants), and ensures the reliability of emergency power (e.g., diesel generator systems). Moreover, neutral grounding can dissipate overvoltages caused by lightning strikes or switching operations, protect the insulation of transformers and lines, and facilitate rapid fault location and resolution, minimizing power outages’ impact on production and emergency supply.

Features and Advantages

The ORLV low-voltage resistor cabinet features high accuracy, excellent linearity, reliable operation, easy installation, and an attractive design. Its internal resistors are made of premium non-metallic special materials or stainless steel nickel-chromium alloy (Cr20Ni80), ensuring stable resistance values, high conductivity, strong current-carrying capacity, and excellent resistance to high temperatures and corrosion. The cabinet is flame-retardant, explosion-proof, and highly reliable overall. It is suitable for various low-voltage distribution systems. In low-voltage networks without a neutral point, the cabinet can be used together with grounding transformers to suppress system overvoltages and effectively mitigate transient surges, thereby enhancing system protection and stability

10 Key Parameters for Selecting Neutral Grounding Resistors (NGR).

How to Accurately Calculate the Neutral Grounding Resistance Value of a Transformer?

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The Most Comprehensive Reference of Grounding Currents and Resistor Values under Different System Voltages

Global Top 8 Neutral Grounding Resistor （NGR）Manufacturers

Technical Parameters：

1. Recommended Technical Parameter Table (OR-LV Series)

Note: If the user has special parameter requirements, customized designs can be provided accordingly.
The resistance value of the cabinet can be designed from 1 Ω to 2000 Ω, with current ratings ranging from 0.5 A to 1000 A.

Dimension Drawing and Wiring Diagram of ORLV Low Voltage Neutral Grounding Resistor Cabinet：

Orion Resistors adopt Fe-Cr-Al stainless steel or Ni-Cr grid resistor elements, featuring excellent stability, high temperature resistance, dense oxide film, and long service life.

All Orion Resistors use high-quality circuit breakers, relays, and surge protectors, combined with intelligent control to ensure coordinated operation and accurate fault current limitation.

Field photos from customer sites, covering substations, power plants, data centers, mining operations, and photovoltaic systems:

Why Choose Orion Resistor:

1..Every resistor and transformer is built with strict quality control and premium materials for long-term reliability.

2.Comprehensive design verification and high-voltage testing guarantee safety and performance before delivery.

3.High-capacity workshops and standardized assembly lines ensure every grounding resistor meets international performance standards.

4.Each NGR cabinet is vacuum-sealed to prevent moisture ingress during transport, ensuring stable insulation resistance and reliable electrical performance upon delivery.