I. Product Overview

Among the types of faults occurring in today’s power supply systems, single-phase-to-ground faults are by far the most common, accounting for more than 70% of all fault occurrences in the power supply system. The frequent occurrence of single-phase-to-ground faults is a major factor contributing to the reduced reliability of power supply systems. By appropriately applying suitable neutral-point grounding methods, we can effectively mitigate the hazards caused by single-phase-to-ground faults and thereby enhance the reliability of power supply.

Currently, in China, the grounding method for the neutral point of transformers in low-voltage distribution systems primarily relies on direct grounding of the neutral point. This method allows for the quick disconnection of the faulty line when a single-phase ground fault occurs, thereby preventing the hazard from spreading further and ensuring the safe operation of the entire system.

However, for certain specialized fields—such as cranes in large-scale power steelmaking workshops, emergency rooms in hospitals, underground drainage and ventilation systems in mining operations, and transformers used to supply power to ships and naval vessels—any power outage in these locations could result in loss of life and property damage. Considering the potential severity of such losses, these special areas adopt a neutral-point-ungrounded grounding system. This grounding method allows the system to continue operating with a single-phase ground fault for an extended period, significantly reducing the disruption caused by power outages resulting from faults.

However, after prolonged use of the ungrounded neutral point system in these special locations, it has been found that although this grounding method can allow equipment to continue operating for a certain period following a fault, due to the unique environmental conditions, single-phase ground faults often go undetected in a timely manner. As a result, equipment remains in a faulty state for an extended period, leading to further escalation of the incident. Therefore, how to enhance power supply reliability and avoid the drawbacks associated with using an ungrounded neutral point system when ground faults occur has become an important technical issue that these locations must address.

After careful research, our company has developed a “Comprehensive Protection Device for the Neutral Point in Low-Voltage Systems.” This system adopts a high-resistance grounding method for the neutral point, fully preserving the advantages of the ungrounded neutral-point configuration. At the same time, it leverages the high-resistance’s ability to absorb ground currents, suppress arc formation, and reduce resonant overvoltages. Additionally, the system incorporates intelligent monitoring, smart communication, and cloud-based data storage features, enabling real-time monitoring of system operating conditions, timely fault alarms, fault-phase analysis, and reduction of hazards at fault locations. This allows personnel to gain a comprehensive understanding of the system’s operational status and clearly identify faulty lines and fault phases, thereby taking prompt corrective actions, providing all-around system protection, and significantly enhancing power supply reliability.

II. Product Features

1. All products use a 32-bit ARM core processor.

2. Utilizing industrial-grade components and parts, the product boasts high reliability and is well-suited to a variety of complex on-site environments.

3. A variety of sensor data fusion technologies enable reliable identification of various faults.

4. An intelligent recognition and fuzzy control algorithm identifies and handles electric shock accidents and ground faults.

5. Industrial-grade 7-inch touch display with a user-friendly human-machine interface and simple operation.

6. High-speed data acquisition system with an accurate data acquisition interval of 2 ms.

7. Data storage function: Stores critical data for 60 minutes or 60 hours, which can be visually viewed through data curves.

8. All critical components have self-diagnostic functions.

9. Upload device data to the cloud.

III. Scope of Application

Crane systems in electric steelmaking workshops, emergency rescue rooms in hospitals, underground drainage and ventilation systems in mining operations, transformers used for power supply on ships and naval vessels, and other low-voltage distribution systems below 10 kV that employ an ungrounded neutral point.

4. Operating Environment Conditions

1. Ambient temperature: -20℃ to +60℃;

2. Relative humidity: 0% to 95%, no condensation;

3. Environment: Free from vibration, dust, corrosive gases, flammable gases, oil mist, water vapor, dripping water, or salt deposits, etc.;

4. Atmospheric pressure: 70–106 kPa;

5. Storage temperature: -40℃ to +80℃;

6. Cooling method: Natural cooling.