Portable reactive power compensation device based on modularized low-voltage transformer area

Abstract

The invention discloses a portable reactive power compensation device based on a modularized low-voltage transformer area, which comprises a controller, a capacitor and a fling-cut switch. The controller is connected to a load main line and is connected with the capacitor through the fling-cut switch, the controller comprises an active module and a passive module, the active module adopts a three-phase three-bridge-arm structure topology in an NPC three-level form, and the passive module adopts an inter-phase capacitor compensation structure without series inductance. The active module and the passive module are perfectly combined, dead-corner-free continuous compensation is achieved, according to the linear dynamic requirement of the system, the output ratio and linear dynamic output of the active / passive module are automatically adjusted, smooth and stable effects are achieved, over-compensation and under-compensation are avoided, meanwhile, the state and the overall operation time of the capacitor are comprehensively monitored, the capacitor is prevented from working with diseases, and the service life is prolonged.

Description

technical field [0001] The invention relates to the field of power distribution technology, in particular to a portable reactive power compensation device based on a modular low-voltage station. Background technique [0002] With the rapid development of social economy and science and technology, high-power electrical equipment is widely used in residents' homes, which adds to the burden on the distribution network with insufficient reactive power allocation. At present, the following problems generally exist in the low-voltage power distribution substation area: [0003] (1) Low power factor: Since the reactive power compensation device generally adopts two methods of contactor group switching and manual group switching of capacitor banks, the compensation is not precise and the low-voltage line is in the state of over-compensation or under-compensation for a long time, and the combination of compensation methods The method is single, and in addition, the general reactive ...

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Problems solved by technology

[0003] (1) Low power factor: Since the reactive power compensation device generally adopts two methods of contactor group switching and manual group switching of capacitor banks, the compensation is not precise and the low-voltage line is in the state of over-compensation or under-compensation for a long time, and the combination of compensation methods The method is single, and in addition, the general reactive power compensation device is installed on the low-voltage side of the transformer, resulting in an increase in line loss;

[0004] (2) Three-phase imbalance: Most of the electrical equipment (such as rice cookers, computers, washing machines, refrigerators, etc.) in the households of users in low-voltage station areas are single-phase electrical equipment. When the single-phase power consumption is different, the three-phase power supply system Three-phase unbalance has become a common phenomenon, and residents' electricity consumption is affected by factors such as seasons, weather, and holidays. There is greater uncertainty in single-phase electricity consumption, which leads to serious three-phase load imbalances in the power supply system. In addition, urban With rapid development and a sharp increase in load, the problem of unbalanced three-phase load becomes more serious during the peak period of power consumption, and the following problems may exist: a. Increase the no-load loss, copper loss and low-voltage line loss of the distribution transformer, compared with the balance Power supply, the power loss caused by unbalanced load is relatively large; b. The voltage drop generated by zero-sequence current and negative-sequence current on the transformer and line leads to abnormal supply voltage at the end, resulting in unbalanced three-phase voltage, and the voltage of some phases is too high or too low, single-phase electrical equipment cannot operate normally, and three-phase electrical equipment stops, which is extremely unfavorable to the safe operation of electrical equipment; c, low-voltage switch single-phase current is too large, which reduces the load capacity of the transformer and is easy to lead to tripping and power outage accidents;

However, the structural components of the device are relatively complicated, the connection method is complicated, and there is a certain difficulty in installing it with the main line, and the cost investment is large.

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