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

1 Overview of Power Transmission and Distribution Lines1.1 Key Characteristics of Power Transmission and Distribution Lines High Maintenance Difficulty: This is mainly due to the wide area covered by power transmission and distribution lines, the harsh terrain of the laying areas, and the impact of seasonal climate changes, all of which contribute to difficult maintenance. High Requirement for Operational Reliability: The reliable operation of power transmission and distribution lines is closely

Low-voltage power distribution lines are widely used across various industries, and the distribution environments are complex and diverse. These lines are accessed not only by professionals but also frequently by non-specialists, significantly increasing the risk of faults. Improper design or installation can easily lead to electric shock (particularly indirect contact), damage to wiring, or even electrical fires.The grounding system is a critical component of low-voltage distribution networks&m

In a newly constructed residential area, a 10kV power line is introduced into the substation. After stepping down the voltage through the transformer's low-voltage side (0.4kV), power distribution is achieved through three levels of distribution boxes: the main distribution board, secondary distribution boards, and tertiary distribution boards.Main Distribution Board Serves as the primary distribution point for the entire project, directly connected to the transformer providing 0.4kV power. Does

Distribution networks, characterized by their wide distribution, large number of equipment, and low insulation level, are prone to insulation accidents caused by overvoltage. This not only reduces the stability of the entire distribution system and the insulation performance of the lines but also has a significant adverse impact on the safe operation of the power grid and the healthy and sustainable development of the power industry.From a circuit perspective, apart from the power source, the po

Substance of Second - harmonic Restraint in Overcurrent ProtectionThe substance of second - harmonic restraint in overcurrent protection is to use the second - harmonic component to judge whether the current is a fault current or an excitation inrush current. When the percentage of the second - harmonic component to the fundamental - wave component is greater than a certain value, it is judged to be caused by the excitation inrush current, and the overcurrent protection is blocked.Therefore, the

Typical Wiring Diagram of 35kV Line Radial π ConnectionWhen a 35kV line adopts a radial power grid structure, a single - side power supply or a double - side power supply radial type can be used according to the situation of the power supply points, and a loop - out interval is reserved at the end of the line.Typical Wiring Diagram of 35kV Line Radial T - ConnectionFor double - radial lines, it is advisable to select a double - side power supply. When the power supply points do not meet t

Fault Transfer VoltageIn low - voltage distribution systems, there is a type of personal electric shock accident where the accident occurrence point and the system fault point are not at the same location. This kind of accident occurs because after a ground fault happens elsewhere, the generated fault voltage is conducted to the metal casings of other equipment through the PE wire or PEN wire. When the fault voltage on the metal casing of the equipment is higher than the human - body safe voltag

Transformer Selection Criteria: Essential Factors for Optimal PerformanceSelecting the appropriate transformer is critical for ensuring power distribution reliability across industrial, commercial, and residential systems. This process requires meticulous evaluation of load dynamics, environmental constraints, and regulatory standards. Below we outline key selection criteria to guide engineers and designers in making informed decisions.1. Maximum Demand AssessmentThe transformer’s capacity (kVA)

1.1 Voltage Qualification Rate ImprovementHigh - voltage single - phase distribution transformers overcome traditional low - voltage distribution drawbacks like line losses, boosting power supply reliability.Low - voltage distribution causes up to 35% voltage drop, disrupting supply. Switching to high - voltage single - phase transformers limits drops to ≤7%, preventing low - voltage issues at user ends. Stable voltage ensures proper appliance operation.1.2 Power Supply Reliability Enhanc

Single - phase distribution transformers, as crucial voltage transformation and power distribution equipment in the power system, are widely used in rural power grids, low - voltage residential areas, and areas with concentrated single - phase loads.With the continuous increase in the proportion of single - phase loads in the distribution network, the failure rate of single - phase transformers has also increased. Timely identification and handling of these faults are of great significance for e