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

On May 7, China's first large-scale integrated wind-solar-thermal-storage comprehensive energy base UHV transmission project—the Longdong~Shandong ±800kV UHV DC transmission project—was officially energized and put into operation. The project has an annual transmission capacity exceeding 36 billion kilowatt-hours, with new energy sources accounting for more than 50% of the total. After commissioning, it will reduce carbon dioxide emissions by approximately 14.9 million tons annually, contributin

Currently, China has achieved certain accomplishments in this field. Relevant literature has designed typical configuration schemes for grounding fault protection in nuclear power plant low-voltage distribution systems. Based on the analysis of domestic and international cases where grounding faults in nuclear power plant low-voltage distribution systems have caused maloperation of transformer zero-sequence protection, the underlying causes have been identified. Furthermore, improvement suggesti

Single-Phase ReclosingAdvantage:When a single-phase-to-ground fault occurs on a line and three-phase auto-reclosing is applied, it results in higher switching overvoltages compared to single-phase reclosing. This is because three-phase tripping interrupts the current at zero-crossing, leaving residual charge voltages on the unfaulted phases—approximately equal to the peak phase voltage. Since the de-energized interval during reclosing is relatively short, the voltage on these unfaulted phases do

On December 2nd, the South Cairo distribution network loss reduction pilot project in Egypt, led and implemented by a Chinese power grid company, officially passed the acceptance inspection by the South Cairo Electricity Distribution Company of Egypt. The comprehensive line loss rate in the pilot area decreased from 17.6% to 6%, achieving an average daily reduction of lost electricity of approximately 15,000 kilowatt-hours. This project is the first overseas distribution network loss reduction p

Eco-friendly gas-insulated ring main units (RMUs) are important power distribution equipment in electrical systems, featuring green, environmentally friendly, and high-reliability characteristics. During operation, arc formation and interruption characteristics significantly affect the safety of eco-friendly gas-insulated RMUs. Therefore, in-depth research on these aspects is of great significance for ensuring the safe and stable operation of power systems. This article aims to investigate the a

(1) The contact gap is primarily determined by insulation coordination parameters, interruption parameters, contact material of the high-voltage SF₆-free ring main unit, and the design of the magnetic blowout chamber. In practical application, a larger contact gap is not necessarily better; instead, the contact gap should be adjusted as close as possible to its lower limit to reduce operating energy consumption and extend service life.(2) The determination of contact overtravel is related to fac

Insulation degradation in power equipment is generally caused by multiple factors. During operation, insulation materials (such as epoxy resin and cable terminations) gradually deteriorate due to thermal, electrical, and mechanical stresses, leading to the formation of voids or cracks. Alternatively, contamination and moisture—such as dust or salt deposition or high-humidity environments—can increase surface conductivity, triggering corona discharge or surface tracking. Additionally, lightning s

Intelligent complete sets of electrical switchgear and intelligent controller products are essential components in the manufacturing of intelligent ring main units (RMUs). The intelligent integration of complete switchgear combines advanced manufacturing technologies with information technology, effectively enhancing the power grid’s capabilities in state awareness, data analysis, decision-making, control, and learning, thereby fully embodying the digital, networked, and intelligent development

Preparatory Work Before Adjusting the Tap Changer of H61 Oil Power 26kV Electric Transformer Apply for and issue a work permit; carefully fill out the operation ticket; conduct a simulation board operation test to ensure the operation is error-free; confirm the personnel who will carry out and supervise the operation; if load reduction is required, notify affected users in advance. Before construction, power must be disconnected to take the transformer out of service, and voltage testing must be

1.Causes of Damage to Agricultural H59/H61 Oil-Immersed Distribution Transformers1.1 Insulation DamageRural power supply commonly uses a 380/220V mixed system. Due to the high proportion of single-phase loads, H59/H61 oil-immersed distribution transformers often operate under significant three-phase load imbalance. In many cases, the degree of three-phase load imbalance far exceeds the limits permitted by operational regulations, causing premature aging, deterioration, and eventual failure of th