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

1. Definition of High-Voltage Cable Line Constant TestingHigh-voltage cable line constant testing refers to the systematic measurement, using specialized instruments, of electrical parameters such as resistance, inductance, capacitance, and conductance before a cable line is commissioned or after major maintenance. The aim is to obtain fundamental data characterizing the electromagnetic properties of the cable, serving as a critical testing phase that provides accurate parameter support for powe

1.Work Environment Requirements and Safeguard MeasuresBased on technical requirements for cable equipment storage, laying, transportation, laying, transposition, testing, and cable terminations, the project owner and construction units have conducted extensive trials and implemented protective measures regarding ambient temperature, humidity, bending radius, traction control, and route optimization. These measures ensure high-voltage cable quality and on-site safety under harsh winter conditions

Withstand voltage test is an insulation test, but it is a destructive test that can reveal insulation defects difficult to detect in non-destructive testing.The test cycle for high-voltage cables is three years, and it must be conducted after non-destructive tests. In other words, the withstand voltage test is performed only after all non-destructive tests have been passed.Most high-voltage cables used today are cross-linked polyethylene (XLPE) cables, which can have large cross-sections and cov

1.Flame-Retardant Cable Classification StandardsThe flame-retardant standard system is divided into two main categories. The first category follows the "Classification of Burning Behavior for Electric and Optical Fiber Cables" GB 31247. Cables complying with this standard system are widely used in densely populated areas such as high-speed railways and subways. This standard imposes strict requirements on parameters such as smoke density, heat release, and total smoke production, and cables typi

For a 24V switch-mode power supply branch, I used a single-pole DC circuit breaker, with the negative pole subjected to equipotential bonding (previously, I even directly used AC breakers as substitutes—the main difference being arc-extinguishing performance, but how significant can the arc be in a few-amp low-current short circuit?).During a design review, an expert stated that DC circuit breakers must be bipolar, arguing that DC has positive and negative poles, unlike AC!I'm puzzled—where is t

1. Issues and Cause Analysis in Smart Electricity Meter TestingDuring the verification of smart electricity meters, inspections must be conducted on the meter’s appearance, as well as the clarity and integrity of nameplate markings. Additionally, careful checks are required for physical damage and whether the display can show digits completely. A power-on inspection is also necessary. If error codes appear on the display after power-up, faults should be identified and addressed according to the

In today's world, not wearing a watch is no longer unusual, but not having an electricity meter is a serious issue. As a measuring instrument vital to people's daily lives, the electricity meter is an essential tool for power consumption measurement and billing in every household. According to current national strategic requirements for smart grid development, smart electricity meters have been widely applied and promoted, bringing entirely new and extensive market opportunities to the metering

Dielectrics and insulators are distinguished primarily by their applications. One of the main differences is that a dielectric can store electrical energy by becoming polarized in an electric field, whereas an insulator resists the flow of electrons to prevent current conduction. Other key differences between them are outlined in the comparison chart below.Definition of DielectricA dielectric material is a type of insulator that contains few or no free electrons. When subjected to an electric fi

The testing of indoor load switches should cover their entire lifecycle, focusing on four core aspects: "ensuring reliable insulation, normal mechanical operation, safe switching capability, and operational compatibility." The main testing categories include:1. Insulation Performance Testing: Use a megohmmeter to measure insulation resistance between phases, from phase to ground, and between moving and fixed contacts (≥0.5 MΩ for low voltage, ≥1000 MΩ for high v

The installation quality of indoor load switches directly affects their operational safety and service life. It must be carried out focusing on four core principles: "safety protection, standardized wiring, mechanical compatibility, and insulation assurance." Specific precautions are as follows:1.Basic Preparation and Safety Protection Before Installation: Verify that the switch model and specifications (e.g., rated voltage, current) match the actual power distribution requirements to avoid "usi