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

Recently, a ±550 kV DC GIS (Gas-Insulated Switchgear), jointly developed by a Chinese GIS manufacturer and multiple companies, successfully completed a 180-day outdoor long-term energized reliability test at the Xi’an High Voltage Apparatus Research Institute. This marks the first time in the industry that a next-generation ±550 kV DC GIS has passed such a long-term energized evaluation.The ±550 kV DC GIS had already undergone comprehensive performance verification tests at the Xi’an High Voltag

Power voltage regulators are a major electrical equipment in distribution substations. Since the power supply capacity of most distribution substations is relatively small, the capacity of voltage regulators is generally below 1000 kV·A. Therefore, voltage regulators are transported to the site as complete units, with all accessories assembled at the factory before shipment. Hence, the installation work of power voltage regulators in distribution substations mainly includes transportation, visua

With the implementation of the EU’s new F-Gas Regulation (Regulation (EU) 2024/573), the power equipment industry is entering a countdown toward environmental transformation. The regulation explicitly prohibits, starting in 2026, the use of fluorinated greenhouse gases in medium-voltage switchgear rated at 24 kV and below. This restriction will be extended to equipment up to 52 kV from 2030 onward, accelerating the industry’s shift away from sulfur hexafluoride (SF₆)—a gas with a high global war

On October 16, a ±800 kV ultra-high-voltage (UHV) transmission project completed all its maintenance tasks and was fully re-energized. During this period, a regional power company successfully conducted the first-ever fully unmanned inspection of the GIS (Gas-Insulated Switchgear) room at a UHV converter station within this power system.As a key component of China’s “West-to-East Power Transmission” strategy, the ±800 kV UHV project has been in operation since 2016 and has delivered nearly 400 b

1. IntroductionSF₆ is widely used in electric power transmission and distribution systems, such as gas-insulated switchgear (GIS), circuit breakers (CB), and medium-voltage (MV) load switches. It possesses unique electrical insulation and arc-quenching capabilities. However, SF₆ is also a potent greenhouse gas, with a global warming potential of approximately 23,500 over a 100-year time horizon, and therefore its use is regulated and subject to ongoing discussions regarding restrictions. Consequ

1.IntroductionIn response to climate change, extensive research and development efforts have been undertaken globally to develop various types of SF₆-free gas-insulated switchgear as alternatives to conventional SF₆-based equipment. On the other hand, SF₆-free gas-insulated switchgear has been in service since the late 1960s. By integrally molding live components of the switchgear using solid insulation materials—such as epoxy resin—with dielectric strength significantly higher than that of SF₆,

What Are the Differences Between Substations, Switching Stations, and Distribution Rooms?A substation is a power facility in the electric power system that transforms voltage levels, receives and distributes electrical energy, controls the direction of power flow, and adjusts voltage. It interconnects power grids of various voltage levels through its transformers. In specific applications—such as submarine power cables or long-distance transmission—some systems use high-voltage direct current (H

First, the installation of 10 kV high-voltage disconnect switches must meet the following requirements. The first step is to select an appropriate installation location, typically near the switchgear power supply in the power system to facilitate operation and maintenance. At the same time, sufficient space must be ensured at the installation site to accommodate equipment placement and wiring.Secondly, equipment safety must be fully considered—for example, lightning protection and explosion-proo

1.IntroductionIn a double-busbar system, line energizing/de-energizing and bus transfer are fundamental switching operations. Under the double-busbar configuration, line protection voltage is derived from busbar potential transformers (PTs). The PTs are connected to the busbar via primary disconnect switches, with their secondary windings routed to the PT secondary terminal box. Each PT has three secondary windings: one for protection and measurement, one for metering, and one open-delta winding

The 145 kV disconnector is a critical switching device in substation electrical systems. It is used in conjunction with high-voltage circuit breakers and plays an important role in power grid operation:First, it isolates the power source, separating equipment under maintenance from the power system to ensure personnel and equipment safety;Second, it enables switching operations to change the system operating mode;Third, it is used to interrupt small-current circuits and bypass (loop) currents.Re