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

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

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

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

Fuses are connected in series in a circuit. When the current through the fuse element is less than or equal to its rated current, the element will not melt. Only when the current exceeds the rated value and reaches the fusing current will the element melt. When a short circuit (or overload) current occurs in the line, the current through the fuse element exceeds the specified value, causing the element to overheat and melt, thereby automatically interrupting the circuit. This prevents damage to

In the power plants and substations of various voltage levels that we operate and maintain, high-voltage current-limiting fuses are widely used, primarily for protecting voltage transformers, small transformers, and small high-voltage motors. So why are they called high-breaking-capacity fuses? And why can't ordinary fuses be used? Today, let's learn about this topic together.High-breaking-capacity fuses, also known as high-voltage current-limiting fuses, differ from ordinary fuses in two main a

Safe operation and regular maintenance of low-voltage pole-mounted circuit breakers are essential for long-term system reliability.1. Operational Safety ProceduresOperations must be strictly regulated under dispatch control, following the "Three Tickets and Two Systems" (work permit, operation ticket, emergency repair order; read-back and supervision systems). Operation tickets must use dual equipment identifiers (e.g., "XX kV XX Line XXX Circuit Breaker") and list detailed steps and safety meas

In the selection process of low-voltage circuit breakers, the following critical factors must be considered:Rated Current and Short-Circuit Breaking Capacity are fundamental to proper selection. According to relevant standards, the rated current of a circuit breaker should be equal to or greater than the calculated load current, with an additional safety margin (typically 1.1 to 1.25 times). Meanwhile, the short-circuit breaking capacity must exceed the maximum prospective short-circuit current

Live-line spraying of PRTV on insulatorsTo ensure the safe operation of transmission lines and effectively prevent pollution flashover, the company's live-line work team recently responded to the local power supply bureau's requirements by conducting live-line spraying of PRTV coating on insulators of relevant transmission lines, equipping the insulators with a bright red "protective coat." The live-line spraying operations were mainly carried out in industrialized towns in central and western C

1. Characteristics of Fully Insulated SF₆ Switchgear1.1 OverviewFully insulated SF₆ switchgear comprises functional units such as load switches, load switch-fuse combinations, disconnectors-circuit breakers, etc., all sealed within stainless steel gas boxes filled with low-pressure SF₆ gas. This gas serves both as the arc-quenching and insulating medium. The switchgear employs electric or manual spring-operated mechanisms. Each cabinet is an independent gas box, allowing for expansion through bu