The basic principle of relay protection tester

The microcomputer relay protection tester can test and verify all relays and protection devices. It is an indispensable test equipment for power plants, power grid companies and various power consumption units. It is used to detect switchgear and comprehensive protection devices, using high-speed digital control processor as the control microcomputer, applying double-precision algorithm, and the relay protection tester can generate arbitrary high-precision waveforms of each phase in the software. In order to play the role of anti-accident automatic device, the relay protection device correctly distinguishes the normal and abnormal operating states of the protected components, external faults and internal faults, so as to realize the function of relay protection. Thereby detecting and identifying the changes of various physical quantities reflected by the protected element in various states. According to the different physical quantities reflected, the protection device can constitute the protection of the following principles:

Relay protection tester reflects the protection of electrical quantities When a power system fails, it is usually accompanied by a decrease in current and voltage, a ratio of current to voltage (impedance), and a change in the phase angle between the two. Therefore, various converters installed at one end of the protected element can detect, compare and identify the differences in these basic parameters under fault and normal operation conditions, and can form various relay protection devices with different principles. For example, reflecting the increase of current constitutes overcurrent protection; low-voltage (or overvoltage) protection is formed by reflecting the decrease (or increase) of voltage; reflecting the change of phase angle between current and voltage constitutes directional protection; relay protection tester voltage Changes in the current ratio constitute distance protection. In addition, differential protection, high frequency protection, etc. It can also be formed according to the difference in current phase or power direction at both ends of the protected component when the protected component is short-circuited inside and outside. Also, sequence component protection is widely used due to its high sensitivity. New protections reflecting fault components, catastrophic and adaptive principles are also applied.

The relay protection tester responds to changes in non-electricity such as temperature, pressure, and flow, and can form gas protection and temperature protection for power transformers. Relay protection is equivalent to an online open-loop automatic control device. According to the nature of the control process signal, it is divided into analog type (divided into electromechanical type and electrostatic type) and digital type. A traditional analog relay protection device generally includes a measurement part, a logic part and an execution part.