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

The rural power grid transformation plays an important role in reducing rural electricity tariffs and accelerating rural economic development. Recently, the author participated in the design of several small-scale rural power grid transformation projects or conventional substations. In rural power grid substations, conventional 10kV systems mostly adopt 10kV outdoor auto circuit vacuum reclosers.To save investment, we adopted a scheme in the transformation that removes the control unit of the 10

An Automatic Circuit Recloser is a high-voltage switching device with built-in control (it inherently possesses fault current detection, operation sequence control, and execution functions without requiring additional relay protection or operating devices) and protective capabilities. It can automatically detect the current and voltage in its circuit, automatically interrupt fault currents according to inverse-time protection characteristics during faults, and perform multiple reclosures accordi

Lightning strikes, fallen tree branches, and even Mylar balloons are enough to interrupt current flow on power lines. That’s why utility companies prevent outages by equipping their overhead distribution systems with reliable recloser controllers.In any smart grid environment, recloser controllers play a critical role in detecting and interrupting transient faults. Although many short circuits on overhead lines can resolve themselves, reclosers help improve service continuity by automatically re

According to statistics, the vast majority of faults on overhead power lines are transient, with permanent faults accounting for less than 10%. Currently, medium-voltage (MV) distribution networks commonly employ 15 kV outdoor vacuum automatic circuit reclosers in coordination with sectionalizers. This setup enables rapid restoration of power supply after transient faults and isolates faulty line segments in the event of permanent faults. Therefore, it is essential to monitor the operational sta

1 Current Grid StatusWith the continuous deepening of rural power grid transformation, the health level of rural grid equipment is constantly improving, and power supply reliability basically meets user needs. However, regarding the current grid status, due to funding constraints, ring networks have not been implemented, dual power supplies are unavailable, and lines adopt a single radial tree-like power supply method. This resembles a tree trunk with many branches—meaning the lines have numerou

1. What is a Recloser?A recloser is an automated high-voltage electrical switch. Similar to a circuit breaker in household electrical systems, it interrupts power when a fault—such as a short circuit—occurs. However, unlike a household circuit breaker that requires manual reset, a recloser automatically monitors the line and determines whether the fault has cleared. If the fault is temporary, the recloser will automatically reclose and restore power.Reclosers are widely used throughout distribut

1. Introduction to Overhead Lines and Reclosers in VietnamVietnam's power distribution landscape is dominated by overhead lines, especially at the 20kV voltage level, which serves both urban centers and rural regions. As of 2024, approximately 65% of Vietnam's 20kV distribution network relies on overhead infrastructure, making it susceptible to environmental factors like lightning, typhoons, and vegetation interference. In this context, reclosers have emerged as critical components to maintain g

1. IntroductionIn power distribution infrastructure, reclosers play a pivotal role in ensuring reliable electricity supply—particularly in countries like Vietnam, where the demand for stable power has grown exponentially with economic development. As of 2024, Vietnam's power grid has formed a complex network, with a significant portion operating at the 20kV voltage level. In this context, reclosers serve as critical components to maintain grid integrity and enhance service quality.2. F

Coordination of Reclosers and Sectionalizers in Distribution NetworksAutomatic reclosers and automatic sectionalizers (reclosers and sectionalizers for short) are relatively complete and highly reliable automated devices. They can not only reliably and promptly eliminate transient faults but also minimize the power outage range caused by permanent faults. Since reclosers and sectionalizers are used in distribution networks, they can selectively and effectively eliminate transient faults to preve

The testing of reclosers in Nigeria is a rigorous, multi-stage process designed to ensure compliance with local regulations, adaptability to harsh environmental conditions, and reliable operation across diverse grid landscapes. Below is an in-depth exploration of the key testing phases and their technical implications:1. Regulatory Compliance: SONCAP Certification and NERC StandardsReclosers entering Nigeria’s market must first navigate mandatory regulatory hurdles. SONCAP certificatio