Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

The neutral grounding mode refers to the connection between the power system neutral point and ground. In China's 35 kV and below systems, common methods include ungrounded neutral, arc-suppression coil grounding, and small-resistance grounding. The ungrounded mode is widely used as it allows short-term operation during single-phase grounding faults, while small-resistance grounding has become mainstream for its fast fault removal and overvoltage limitation. Many substations install grounding tr

With the increasing complexity of power system operation environment and the deepening of power system reform, traditional power grids are accelerating the transformation to smart grids. The goal of equipment condition-based maintenance is achieved through real-time perception of equipment status by new sensors, reliable communication via modern network technology, and effective monitoring by background expert systems.I. Analysis of Condition-based Maintenance StrategyCondition-based Maintenance

With the accelerated automation of power equipment, various medium-voltage switchgear have emerged in the market. Classified by insulation media, they are mainly divided into air-insulated, SF₆ gas-insulated and solid-insulated types, each with its own advantages and disadvantages: solid insulation offers good performance but poor environmental friendliness, SF₆ features excellent arc extinguishing capability but is a greenhouse gas, and air insulation has high cost-performance but larger volume

As an expert who has been deeply engaged in the field of power system design for many years, I have always paid attention to the technological evolution and application practice of medium-voltage ring main distribution equipment. As a core electrical device in the secondary distribution link of the power system, the design and performance of such equipment are directly related to the safe and stable operation of the power supply network. The following is a professional analysis of the key design

1. Statistics on Common Faults of Medium-Voltage Switchgear in the Early Operation StageAs project participants, we found during the early operation of a new metro line: 21 sets of power supply equipment were put into use, with a total of 266 accident phenomena in the first year. Among them, 77 faults occurred in medium-voltage switchgear, accounting for 28.9%—significantly higher than faults in other equipment. Statistical analysis shows that major fault types include: protection devi

Due to the long service life and severe aging of the equipment, the switches in the 6kV working section of Unit 6 of a certain power plant have potential safety hazards such as deformed locating pins, abnormal closing positions of the earthing switches, and malfunctions of the protection devices. These hazards have threatened the stable operation of the unit, making the transformation extremely urgent. Meanwhile, considering the recent cases of electric shock casualties involving medium-voltage

As a professional engaged in power system operations, I recognize that medium-voltage (MV) switchgear plays a pivotal role in power distribution, metering, and protection. Ensuring its operational safety and reliability is critical—any malfunction can severely disrupt the entire power system. To enhance reliability, we must prioritize design-level optimizations, enabling MV switchgear to fulfill its functions and safeguard grid stability.1. Definition of Medium-Voltage SwitchgearIn my

I. Overvoltage PreventionVacuum circuit breakers excel in interrupting performance, but high overvoltage may occur across inductors during the switching of inductive loads due to abrupt changes in loop current, which requires special attention. When switching small-capacity motors, starting currents are large, so measures like step-down starting should be adopted to limit the current.Transformers with different structures show distinct characteristics: oil-immersed transformers have high impulse

In the first half of 2007, as project participants from the Electromechanical Equipment Company of Huaibei Mining Group, we carried out a technical transformation of the 10kV substation in the East Factory Area. Our primary task was to replace the original 10kV disconnector - oil - immersed circuit breaker units with ZN20 indoor high - voltage vacuum circuit breakers.Previously, the SN10 - 10 oil - immersed circuit breakers had been in operation for an extended period, leading to severe oil leak

Inability to Push In or Withdraw the Draw-out CarriageThe main manifestation is difficulty in inserting the carriage, which may cause equipment damage and threaten production when severe. The causes and countermeasures are shown in Table 1.The circuit - breaker fails to close. It manifests as the closing core actuating but the circuit - breaker not closing successfully; or the closing core not actuating, which shows that the control circuit of the circuit - breaker is open - circuited or the mec