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

First of all, it must be clarified: AC circuit breakers must not be used to replace DC circuit breakers in DC circuits!Due to differences in arc generation and extinction processes between AC and DC, AC and DC circuit breakers with the same rated values do not have identical capabilities when interrupting DC power. Using AC circuit breakers in place of DC ones, or mixing AC and DC breakers, is one of the main causes of protection miscoordination and unintended upstream tripping.Circuit breakers

Fully electric commercial vessels are becoming increasingly popular, with DC power systems being the preferred choice for onboard power distribution due to their ability to handle high power flows within limited space at higher system efficiency and lower lifecycle costs.Commercial vessels equipped with onboard DC grids have proven capable of operating at peak energy efficiency while minimizing emissions. This results in significant power savings and reduced operating costs across maritime appli

1. Security Threats Facing Smart Meter Communications1.1 Physical Layer Security ThreatsPhysical layer security threats refer to factors that damage or interfere with the hardware devices and physical connections of smart meters, directly affecting their normal operation and data transmission. From the perspective of equipment damage, harsh natural environments such as lightning strikes, floods, and earthquakes can directly destroy the hardware circuits and structures of smart meters, rendering

Meter reading, verification, and billing are critical operations for power companies, and their efficiency directly impacts the company's sustainable development. In recent years, with the widespread adoption of intelligent technologies, smart meters have been promoted and applied in power companies, driving transformation in meter reading and billing operations. The integrated application of smart meters and meter reading, verification, and billing information systems has become a key developme

In indoor switchgear rooms, indoor load switches are key devices designed to meet the core requirements of "medium and low-voltage distribution, flexible control, and simplified protection." Their application centers on three primary scenarios: "circuit control, safety isolation, and fault coordination." The specific implementation methods and value are as follows:1.Power Control Unit for Terminal Loads: Load switches are commonly used in branch circuits of low-voltage distribution panels within

What is a Load Switch?A load switch is a control device equipped with a simple arc-extinguishing mechanism, capable of opening and closing circuits under load. It can interrupt a certain level of load current and overload current, but cannot interrupt short-circuit current. Therefore, it must be used in series with a high-voltage fuse, which relies on the fuse to clear short-circuit currents.Functions of a Load Switch: Switching and Closing Function: Due to its certain arc-extinguishing capabili

Medium-voltage current-limiting fuses are primarily used for protecting loads such as transformers and motors. A fuse is a device that, when the current exceeds a given value for a sufficiently long duration, interrupts the circuit in which it is inserted by melting one or more specially designed and proportioned components. Current-limiting fuses may have difficulty clearing intermediate current values (overloads between 6 to 10 times the rated current), so they are typically used in combinatio

High-voltage disconnect switches (or fuses) do not have arc-extinguishing capability, but they provide a clearly visible break point. Therefore, they are used solely as isolation components in a circuit. They are installed at the beginning of a circuit or in front of components requiring maintenance. When a circuit needs to be de-energized for maintenance, the power is first interrupted using a switching device, and then the disconnect switch is opened. This ensures a clearly visible break in th

1 Introduction to Fault Current Limiter (FCL) TechnologyTraditional passive fault current limitation methods—such as using high-impedance transformers, fixed reactors, or split-busbar operation—suffer from inherent drawbacks, including disruption of grid structure, increased steady-state system impedance, and reduced system security and stability. These approaches are becoming increasingly unsuitable for today's complex and large-scale power grids.In contrast, active fault cu

1 Locations for Installing Fault Current Limiters (FCLs) At Generator Terminals：Installing an FCL at this location reduces the short-circuit current level in the grid during faults, minimizes mechanical and thermal stress on the generator, and consequently reduces losses in equipment and devices. At Plant Distribution Substations：Short-circuit current levels at this location are typically very high. Installing an FCL can significantly suppress fault currents. Across the Entire Busbar：When increa