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

The following are methods for handling accidents and abnormalities related to isolating switches:(1) If an isolating switch fails to operate (refuses to open or close), take the following steps:① For mechanically operated isolating switches that fail to open or close, check whether the circuit breaker is open, whether the mechanical interlock of the isolating switch has been released, whether the transmission mechanism is jammed, and whether the contacts are rusted or welded. Gently wiggle the o

When performing switching operations, operating personnel must carefully verify that the circuit breaker is indeed in the open position. For three-pole interlocked isolating switches, all three phases must move simultaneously, with a maximum allowable vertical discrepancy of no more than 3 mm, before any opening or closing operation of the isolating switch is permitted.1. Key Points for Closing an Isolating SwitchFor manual operation, operating personnel should first remove the interlock pin bef

In substations, the number of isolating switches is generally 2 to 4 times that of circuit breakers. Due to their large quantity, the workload for installation and commissioning is considerable. For voltage levels below 110 kV, the GW4-type isolating switch serves as the dominant equipment. If the installation workmanship and mechanical dimensional adjustments of the isolating switch do not meet requirements, issues such as incomplete opening/closing, overheated contacts, or even porcelain insul

Overheating of Busbar Isolating Switches: Causes and Handling ProceduresOverheating of busbar isolating switches is a common electrical equipment defect. If not addressed promptly, the situation can severely deteriorate during a system short circuit—when high short-circuit current flows through the overheated point, potentially causing contact melting or even destruction of the switch.When overheating of a busbar isolating switch is detected, follow these steps for safe handling: Report the defe

Isolating Switch: Definition and OverviewAn isolating switch (or disconnector) is a switching device primarily used for isolating power sources, switching operations (bus transfer), and making or breaking small-current circuits. It has no arc-quenching capability.When in the open position, there is a specified insulation distance between contacts and a clearly visible disconnection indicator. When in the closed position, it can carry the normal operating current and, for a specified duration, th

Causes of High Temperature in Isolating Switches of Capacitor Banks and Corresponding SolutionsI. Causes: OverloadThe capacitor bank is operating beyond its designed rated capacity. Poor ContactOxidation, loosening, or wear at contact points increases contact resistance. High Ambient TemperatureElevated external environmental temperatures impair the switch’s ability to dissipate heat. Inadequate Heat DissipationPoor ventilation or dust accumulation on heat sinks hinders effective cooling. Harmon

Application of Isolating Switches in Generator Neutral Grounding Resistor CabinetsIsolating switches are commonly installed in NS-FZ generator neutral grounding resistor cabinets. They provide a clearly visible disconnection point, ensuring the safety of maintenance and testing personnel. However, as high-voltage devices without arc-quenching capability, isolating switches must only be operated when the circuit is de-energized—i.e., under no-load conditions.The primary function of an isolating s

Differences Between Centralized and Distributed Photovoltaic (PV) Power PlantsA distributed photovoltaic (PV) power plant refers to a power generation system that consists of multiple small-scale PV installations deployed across various locations. Compared to traditional large-scale centralized PV power plants, distributed PV systems offer the following advantages: Flexible Layout: Distributed PV systems can be flexibly installed based on local geographic conditions and electricity demand—in div

How to Select Low-Voltage Electrical Apparatus: Two Key Principles and Four Important ConsiderationsWhen selecting low-voltage electrical devices, two fundamental principles must be followed: safety and economy. Additionally, there are several critical factors to consider. Those unfamiliar with the process should refer to the guidelines below.I. Two Core Principles for Selecting Low-Voltage Electrical Apparatus Safety PrincipleThe selected low-voltage devices must operate accurately and reliably

A sewage pump control panel suddenly suffered a catastrophic failure—the control transformer literally caught fire and burned to a charred mess, completely catching us off guard. With no spare parts available in the warehouse and work needing to continue, we had to think fast.From the circuit diagram, it’s clear that this pump control panel operates on a 660V AC power system, but its control circuit still uses 220V AC—essentially the same as standard distribution panels. The burnt-out transforme