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

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

What lightning protection measures are used for H61 distribution transformers?A surge arrester should be installed on the high-voltage side of the H61 distribution transformer. According to SDJ7–79 "Technical Code for Design of Overvoltage Protection of Electric Power Equipment," the high-voltage side of an H61 distribution transformer should generally be protected by a surge arrester. The grounding conductor of the arrester, the neutral point on the low-voltage side of the transformer, and the

Measures to Prevent H59 Oil Immersed Power Distribution Transformer from Burning OutIn power systems, H59 Oil Immersed Power Distribution Transformer play an extremely critical role. Once burned out, they can cause widespread power outages, directly or indirectly affecting the production and daily lives of a large number of electricity users. Based on the analysis of multiple transformer burnout incidents, the author believes that a considerable number of such failures could have been avoided or