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

What is a microcomputer protection device?Answer: A microcomputer protection device is an automatic device that can detect faults or abnormal operating conditions in electrical equipment within a power system, and act to trip circuit breakers or issue alarm signals.What are the basic functions of microcomputer protection?Answer: Automatically, rapidly, and selectively isolate faulty equipment from the system by tripping circuit breakers, ensuring non-faulty equipment resumes normal operation qui

Retrofitting microcomputer protection devices in substations should follow specific steps and precautions. A possible retrofit plan is as follows: Investigate the current status: Understand the types, specifications, operating conditions, and existing issues of the microcomputer protection devices in the substation to provide a basis for the retrofit. Develop a retrofit plan: Based on the investigation and requirements, create a detailed plan including specific tasks, technical specifications, i

1. Selection of Test InstrumentsThe main test instruments for microcomputer protection devices are: microcomputer relay protection tester, three-phase current generator, and multimeter. For testing high-voltage microcomputer protection devices, it is recommended to use a microcomputer relay protection tester capable of simultaneously outputting three-phase voltage and three-phase current, and equipped with timing function for digital inputs. For testing low-voltage microcomputer protection devic

I. BackgroundWith the advancement of intelligent power systems, microcomputer protection devices have become core components in modern industrial power distribution systems due to their high precision, multifunctionality, and reliability. Taking the power distribution project of a natural gas recovery station in the Middle East as a case study, this paper explores the critical role of AM series microcomputer protection devices in enhancing system safety, reliability, and automation levels, and a

1.Selection and Role of Microcomputer Integrated Protection Devices1.1 Selection of Microcomputer Integrated Protection DevicesTo ensure a microcomputer integrated protection device correctly and accurately performs its relay protection tasks, selection during design should comprehensively consider reliability, response time, maintenance and commissioning, and additional functions.Signal input for microcomputer integrated protection devices is the same as traditional relay protection: voltage an

Accurate time relay measurement requires systematic steps to ensure reliable results. Before measurement, confirm the relay model, rated parameters, and operating environment, maintaining ambient temperature at 20±5°C and humidity below 85%RH. Prepare a high-precision timer (resolution 0.001s), regulated power supply (±1% fluctuation), standard load (matching contact rating), and digital multimeter.Calibrate the timer and power supply, ensuring equipment error is within ±0.5%. Mount the relay on

Time relays are commonly used industrial control devices. Based on their timing characteristics, they can be classified into three types: on-delay, off-delay, and combined on/off-delay relays. Among these, on-delay time relays are the most widely used and readily available in the market. However, many on-delay relays have a limited number of contacts and only provide timed contacts without instantaneous ones, which poses inconvenience for electrical control circuit designs requiring immediate re

To ensure safe and stable grid operation and prevent load current surges from damaging electrical equipment during power restoration, all loads connected to distribution transformers must be disconnected before energizing.Therefore, low-voltage circuit breakers are equipped with an undervoltage release function: when a transformer is de-energized due to maintenance or line faults, the loss of voltage on the low-voltage bus causes the branch circuit breaker to trip automatically. After the transf

In electrical and electronic engineering, time relays are crucial control components. Operating on electromagnetic or mechanical principles, they delay the closing or opening of contacts within control circuits. This time-delayed action enables circuits to automatically perform specific operations after a set interval. Based on their timing characteristics, time relays are primarily classified into two types: on-delay and off-delay.1. On-Delay Time RelayAn on-delay time relay does not respond im

Common Faults and Troubleshooting:(1) Over time, the adjustable potentiometer used to set the delay time may suffer wear of the carbon film or accumulate dust, leading to inaccurate timing. To address this, apply a small amount of electrical contact cleaner around the potentiometer shaft, then rotate the shaft back and forth to clean the internal contacts. If the potentiometer is severely worn, replace it promptly.(2) Damage or aging of transistors can alter the parameters of the timing circuit,