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

How to Select and Set Circuit Breakers1. Types of Circuit Breakers1.1 Air Circuit Breaker (ACB)Also known as a molded frame or universal circuit breaker, all components are mounted within an insulated metal frame. It is typically open-type, allowing easy replacement of contacts and parts, and can be equipped with various accessories. ACBs are commonly used as main power supply switches. Overcurrent trip units include electromagnetic, electronic, and intelligent types. They provide four-stage pro

Basic Composition and Function of Circuit Breaker Failure ProtectionCircuit breaker failure protection refers to a protective scheme that operates when the relay protection of a faulty electrical device issues a trip command but the circuit breaker fails to operate. It uses the protection trip signal from the faulty equipment and the current measurement from the failed breaker to determine breaker failure. The protection can then isolate other relevant breakers within the same substation in a sh

Power Supply Procedure for Low-Voltage Electrical RoomsI. Pre-Power-On Preparations Clean the electrical room thoroughly; remove all debris from switchgear and transformers, and secure all covers. Inspect busbars and cable connections inside transformers and switchgear; ensure all screws are tightened. Live parts must maintain adequate safety clearance from cabinet enclosures and between phases. Test all safety equipment before energizing; use only calibrated measuring instruments. Prepare fire-

Optimization and Key Considerations for Operation and Maintenance Management of Low-Voltage Distribution NetworksWith the rapid development of China's power industry, operation and maintenance (O&M) management of low-voltage distribution networks has become increasingly important. A low-voltage distribution network refers to the power supply lines between a power transformer and end-user equipment, forming the most fundamental and critical part of the power system. To ensure its normal opera

Maintenance Procedure for Low-Voltage Power Distribution FacilitiesLow-voltage power distr ibution facilities refer to the infrastructure that delivers electrical power from a power supply room to end-user equipment, typically including distribution cabinets, cables, and wiring. To ensure the normal operation of these facilities and guarantee user safety and power supply quality, regular maintenance and servicing are essential. This article provides a detailed introduction to the maintenance pro

Low-Voltage Electrician Safety Operating Procedures1. Safety Preparation Before performing any low-voltage electrical work, personnel must wear approved protective equipment, including insulating gloves, insulating boots, and insulating workwear. Carefully inspect all tools and equipment for proper operation. Report any damage or malfunction immediately for repair or replacement. Ensure adequate ventilation at the worksite. Avoid prolonged work in confined spaces to prevent fire hazards or poiso

1. Ring Main Unit (RMU) and Transformer SubstationThe ring main unit (RMU) and transformer substation is a critical terminal in a distribution ring network system. The operational status of this terminal is directly affected by the performance of the distribution ring network system. Therefore, this section discusses the advantages, system composition, and key characteristics of the distribution ring network.1.1 Advantages of RMU and Transformer SubstationDue to technological limitations, radial

Differences Between Ring Main Units (RMUs) and SwitchgearIn power systems, both ring main units (RMUs) and switchgear are common distribution equipment, but they differ significantly in function and structure. RMUs are primarily used in ring-fed networks, responsible for power distribution and line protection, with the key feature being multi-source interconnection through a closed-loop ring network. Switchgear, as a more general-purpose distribution device, handles power reception, distribution

Currently, China's medium-voltage distribution networks predominantly operate at 10kV. With rapid economic development, power loads have surged, increasingly exposing the limitations of the existing power supply methods. Due to the outstanding advantages of 24kV high-voltage switchgear in meeting higher load capacity demands, it has quietly gained traction within the industry. Following the State Grid Corporation's "Notice on Promoting the 20kV Voltage Level," the 20kV voltage class has seen a r

I. Research BackgroundPower System Transformation NeedsChanges in energy structure are placing higher demands on power systems. Traditional power systems are transitioning toward new-generation power systems, with the core differences between them outlined as follows: Dimension Traditional Power System New-Type Power System Technical Foundation Form Mechanical Electromagnetic System Dominated by Synchronous Machines and Power Electronic Equipment Generation-Side Form M