A control method for 66kv high-voltage direct-mounted reactive power generator

Abstract

The invention discloses a control method for a 66 KV high-voltage directly-hung var generator. According to the control method, negative sequence voltage feedforward control is provided so that equipment can operate normally when voltage is unstable; a phase-locked loop can be adjusted automatically so that a phase angle can be accurately locked under the severe conditions that voltage distortion exists, harmonic waves exceed the standard and a negative sequence exists; according to the IPIQ instantaneous reactive power theory, positive-sequence reactive currents of a fundamental wave can be output accurately under the severe conditions that system voltage distortion exists, the harmonic waves exceed the standard and the negative sequence exists. According to the method, the 66 KV high-voltage directly-hung var generator has better performance in response speed and in the aspects of stabilizing the network voltage, reducing system loss, increasing transmission capacity, increasing the transient voltage limit, reducing the harmonic wave, reducing the occupied area and the like.

Description

technical field [0001] The invention relates to a power electronic detection control and power quality control device used in a power system, in particular to a novel 66kV high-voltage direct-mounted reactive power generator device, which can be widely used in various power systems. Background technique [0002] With the improvement of social industrialization level, more and more high-power and non-linear equipment enter the power grid, and the power quality pollution it brings is also becoming more and more serious. Especially with the development of power electronics technology, non-linear power electronic devices have been widely used in modern industry. The operation of these devices makes reactive power fluctuations in the power grid more and more serious, and voltage and current waveform distortions become more and more serious. Harmonic levels In addition, the use of impact and fluctuating loads will also cause power quality problems such as voltage fluctuations and ...

AI Technical Summary

Problems solved by technology

[0003] (1) The increase of reactive power will lead to the increase of apparent power and current, which will increase the capacity of equipment in the grid

At the same time, the capacity of start-up and control equipment and measuring instruments of power users should also be increased;

[0004] (2) The increase of reactive power increases the total current, thus increasing the loss of equipment and lines;

[0005] (3) Reactive power will also increase the voltage drop of lines and transformers, and if it is an impact load, it will also cause violent fluctuations in voltage;

[0006] (4) Reactive power can cause the power factor to drop, which reduces the power supply efficiency and increases the power grid loss, which not only causes economic losses to the power supply department, but also increases the user's electricity bill (including fines from the power supply department);

[0007] (5) Harmonics cause additional harmonic losses in the equipment in the power grid, thereby reducing the efficiency of power generation, transmission and power consumption equipment;

[0008] (6) Harmonics generate additional thermal effects, which cause heating of electrical equipment (rotating motors, capacitors, transformers), aging insulation, reducing the service life of equipment, and even being damaged;

[0009] (7) Harmonics lead to inaccurate measurement of electrical measuring instruments, interfere with adjacent electronic equipment and communication systems, and cause some protective equipment to malfunction, such as relay protection, fuses, etc.;

Harmonics are easy to cause parallel or series resonance between the power grid and the compensation capacitor, amplifying the harmonic current several times or even dozens of times, causing overcurrent, and causing damage to the capacitor, the reactor and the resistor connected to it

[0011] At present, parallel passive filters and static dynamic reactive power compensation SVC devices are usually used to suppress harmonics and compensate reactive power, but they have long response time, poor filtering ability, large power loss, easy to resonate with the grid system, and occupy an area. Key defects such as large area

With the development of high-power power electronics technology, static var generators have gradually entered the practical stage, but for power systems with a voltage level of 66kV, currently static var generators can only be connected to the grid through a step-up transformer, so Increase the cost and floor area of ​​the equipment, and also greatly increase the overall loss of the equipment

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