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

Power Transformers: Short Circuit Risks, Causes, and Improvement MeasuresPower transformers are fundamental components in power systems that provide energy transmission and are crucial induction devices ensuring safe power operation. Their structure consists of primary coils, secondary coils, and an iron core, utilizing the principle of electromagnetic induction to alter AC voltage. Through long-term technological improvements, the reliability and stability of power supply have continuously enha

Growing Requirements for Power Transformer Cooling Systems and the Function of CoolersWith the rapid development of power grids and the increase in transmission voltage, power grids and electricity users are demanding increasingly higher insulation reliability for large power transformers. Since partial discharge testing is non-destructive to insulation yet highly sensitive, effectively detecting inherent defects in transformer insulation or safety-threatening defects generated during transporta

General Requirements for Power Transformer Cooling Systems All cooling devices shall be installed in accordance with the manufacturer's specifications; The cooling system with forced oil circulation must have two independent power supplies with automatic switching capability. When the working power supply fails, the standby power supply shall be automatically activated while emitting audible and visual signals; For transformers with forced oil circulation, when a faulty cooler is disconnected, a

1. OverviewDue to global warming, reducing greenhouse gas emissions is a critical issue. A significant portion of losses in power transmission systems comes from power transformers. To reduce greenhouse gas emissions in power systems, more efficient transformers must be installed. However, more efficient transformers often require more manufacturing materials. To determine the optimal loss ratio and manufacturing price of transformers, the Total Cost of Ownership (TCO) method is the industry sta

1.Neutral Point Establishment and System StabilityIn photovoltaic power stations, grounding transformers effectively establish a system neutral point. According to relevant power regulations, this neutral point ensures the system maintains certain stability during asymmetric faults, functioning like a "stabilizer" for the entire power system.2.Overvoltage Limitation CapabilityFor photovoltaic power stations, grounding transformers can effectively limit overvoltages. Generally, they can control o

1. Zero-Sequence Overcurrent ProtectionThe operating current for zero-sequence overcurrent protection of grounding transformers is typically determined based on the transformer's rated current and the maximum allowable zero-sequence current during system ground faults. The general setting range is approximately 0.1 to 0.3 times the rated current, with operating time usually set between 0.5 to 1 second to quickly clear ground faults.2.Overvoltage ProtectionOvervoltage protection is a critical com

1. High-Resistance Grounding SystemHigh-resistance grounding can limit ground fault current and appropriately reduce ground overvoltage. However, there is no need to connect a large high-value resistor directly between the generator neutral point and ground. Instead, a small resistor can be used together with a grounding transformer. The primary winding of the grounding transformer is connected between the neutral point and ground, while the secondary winding is connected to a small resistor. Ac

1. SF6 gas leakage occurred in the ABB LTB 72 D1 72.5 kV circuit breaker.Inspection revealed gas leakage at the fixed contact and cover plate area. This was caused by improper or careless assembly, where the dual O-rings slipped and were misplaced, resulting in gas leakage over time.2. Manufacturing Defects on the Outer Surface of 110kV Circuit Breaker Porcelain InsulatorsAlthough high-voltage circuit breakers typically have their porcelain insulators protected with covering materials during tra

1. What are the characteristic parameters of the coil current waveform in high-voltage circuit breaker operating mechanisms? How to extract these characteristic parameters from the original trip coil current signal?Answer: The characteristic parameters of the coil current waveform in high-voltage circuit breaker operating mechanisms may include the following: Steady-state peak current: The maximum steady-state current value in the electromagnet coil waveform, representing the position where the

According to the "Eighteen Major Anti-Accident Measures for Power Grid of State Grid Corporation of China (Revised Edition)" promulgated in 2018, operation and maintenance units should improve the on-site operation regulations for intelligent substations, refine the usage instructions and abnormal handling methods for various messages, signals, hard pressure plates, and soft pressure plates of intelligent equipment, standardize the operation sequence of pressure plates, strictly follow the seque