Technical Knowledge Sharing

Which Generators Need Generator Protection Relays?

Generators can experience stator winding faults, earth faults, overloads, loss of excitation, reverse power, and abnormal voltage or frequency conditions. Hydro, steam turbine, diesel and gas generators all require protection suited to their operating conditions. Every generator needs appropriate protection, but not every generator requires a separate generator protection relay. On smaller units, the required […]

2026-10-28

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11 kV Medium Voltage Switchgear: Types, Applications and Selection Guide

1. What Is 11 kV Medium Voltage Switchgear? 11 kV medium voltage switchgear is an assembly of switching, protection, measurement and control equipment used to receive and distribute electrical power in an 11 kV network. It is commonly installed in substations, industrial facilities, power plants, renewable energy projects and commercial distribution systems. Depending on the […]

2026-10-27

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Voltage Protection Relays: Types, Functions, Applications and Selection Guide for 33 kV and 11 kV Systems

A voltage protection relays monitors electrical voltage and responds to abnormal conditions. When it detects overvoltage, undervoltage, residual overvoltage, three-phase voltage unbalance or phase loss, the relay evaluates the measured values against its configured settings and operating delays. Depending on the protection scheme, it can issue an alarm, trip command or control signal. Voltage protection […]

2026-10-27

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Types of Electrical Distribution Boxes: Classification & Selection Guide

1. What Is an Integrated Electrical Distribution Assembly? An integrated electrical distribution assembly combines multiple electrical functions—such as power distribution, protection, measurement, energy metering, control and communication—within a single enclosure or cabinet. Depending on the application, it may also provide reactive power compensation, power quality monitoring and remote automation functions. In this article, integrated electrical […]

2026-10-25

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Main Advantages of Ring Main Units (RMUs)

A ring main unit (RMU) is a type of medium-voltage (MV) switchgear widely used in electrical distribution systems, including 10 kV, 11 kV, 20 kV, 22 kV and 33 kV distribution networks. The applicable voltage levels depend on the rated characteristics and design of the equipment. RMUs are widely used in urban distribution networks, industrial […]

2026-10-24

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What Is a PV Combiner Box? Functions, Working Principles and Applications

A PV Combiner Box (Photovoltaic DC Combiner Box) is an electrical distribution and protection enclosure designed to combine the DC outputs of multiple photovoltaic (PV) strings into one or more DC output circuits before connecting them to a solar inverter or other downstream DC equipment. A PV combiner box simplifies DC cabling, provides overcurrent and […]

2026-10-24

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3-Phase Motor Protection Relays: Selection Guide, ANSI Functions & Configuration

1. Overview of 3-Phase Motor Protection Relays A 3-phase motor protection relay is a numerical protection device designed to monitor three-phase alternating-current (AC) motors and protect them against electrical faults, thermal overload, abnormal starting conditions and operational disturbances. Three-phase motors are widely used in power generation, petrochemical plants, mining operations, water treatment facilities, manufacturing plants […]

2026-10-21

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Switchgear Protection Relays Selection Guide: Types, ANSI Protection Functions, Technical Specifications and Applications

Switchgear protection relays are essential secondary protection devices in medium-voltage power distribution systems. They detect electrical faults and abnormal operating conditions, including short circuits, earth faults, overloads, voltage abnormalities and equipment-related faults. When predefined protection criteria are satisfied, the relays initiate alarms or issue trip commands to circuit breakers to isolate the affected circuits. In […]

2026-10-20

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