|
First, the distribution of the importance of reactive power compensation
Currently set off a worldwide wave of environmental protection, electric power system is a specific environment, appearing in the transmission and distribution network reactive power, power itself is determined by operation of the law, but it gives a lot of trouble grid operation . Reactive power is both can not be active, but it will cause losses in the grid, and it is not a lack of power, so you want to add in the grid reactive power compensation device, while the grid voltage is adjusted achieve power efficiency maximized.
一、输配电网无功补偿的重要性
目前世界范围内掀起环境保护的热潮，电力系统是一种特定的环境，在输配电网中出现的无功功率，是电网本身的运行规律所决定，但同时它给电网运行带来了许多麻烦。无功功率是一种既不能作有功，但又会在电网中引起损耗，而且又是不能缺少的一种功率，所以在电网中要加入无功功率补偿的装置，同时对电网电压进行调整，达到电网利用效率最大化。
Second, the distribution of reactive power compensation? 1 grid reactive power compensation http://www.ukassignment.org/dxessay/
二、输配电网的无功补偿？ 1.输电网的无功补偿
Reactive power compensation of the basic principles are: stratified according to the voltage at the grid partition, local equilibrium, avoiding long-range transport of reactive power, so as not to take up the line to increase transmission capacity and power loss. Most no direct supply grid load, generally do not set up for the purpose of regulating reactive power compensation device. Parameters used for longer distances compensated transmission lines. Specific compensation method is as follows:
电网无功补偿的基本原则是：按电压分层，按电网分区，就地平衡，避免无功功率的远距离输送，以免占用线路输送容量和增加有功损耗。输电网多数无直供负载，一般不为调压目的而设置无功补偿装置。参数补偿多用于较长距离的输电线路。具体补偿方法如下：
(A) reactor compensation
Reactors are commonly used in EHV transmission lines over long distances compensation device to compensate for transmission line-to-ground capacitance charging power generated to suppress power frequency overvoltage. The capacity of the reactor length and over-voltage limiting circuit level selection, the degree of compensation (reactor capacity and line charging power ratio) to statistics mostly 70-85, the individual is 65, generally not less than 60. Reactor general often set in the line two turbulent, and does not set the circuit breaker.
(2) series capacitor compensation
Series capacitor is used to compensate for transmission line inductance, improving stability play a shortened electrical distance transmission capacity levels and the role of the line. Series capacitor banks, mostly in series or parallel combination of parallel count by the line transmission capacity, depending on the series by the required number of series capacitor compensation degree (series capacitor compensated line capacitance and inductance ratio) be. Series capacitor compensation is generally below 50, not too high, so as not to cause the system to sub-synchronous resonance. Grid impedance caused by uneven due to circulation, the series capacitor can also be used to compensate. Japan 110kV ring on the use of series capacitor compensation.
(3) intermediate synchronous or static compensator
The intermediate transmission line installed in the remote camera or static synchronous compensator compensating means, use of these devices of reactive power regulation, the line absorbs light load line charging power, limit the voltage rise; issued when the line reactive power overload, to compensate for line reactive power loss, support for voltage levels, thereby increasing the transmission capacity of the line. Middle synchronous or static compensator usually located in the midpoint of the line, assuming that the first end of the line, adjust the effect disappeared.
Anchor with the grid voltage regulator and the power transmission grid region's low a voltage grids associated pivot point, often set OLTC or a substantial ability to regulate and control the reactive power compensation device, or two who have, in order to achieve the central point regulator, so that the operation of the grid is not less affected by the trend changes or other reasons due to the formation of voltage fluctuations in the power grid accident play a supportive role of voltage, and prevent the grid voltage fluctuations The expansion of the accident.
The strength of the voltage support capabilities, in addition to compensation and compensation capacity with the size, but also with the ability to control compensation device regulation and response speed. Although it is commonly used shunt capacitor compensation equipment and inexpensive, but its reactive power output when the voltage drop will be the square of the voltage drop is not conducive to supporting voltage. Instead, a large number of parallel compensation capacitor installed an incident fueled the possibility of the collapse of the grid voltage. Using synchronous condenser and static reactive power compensation device supported by appropriate regulation and control, is an ideal support voltage reactive power compensation device. In recent years, both at home and abroad focus on the application of static compensator.
(2) with reactive power compensation
Distribution network mainly in reactive power compensation phase compensation and guarantees the quality of the main users of electricity voltage. Specific methods for the phase compensation.
(A) phase compensation (also known as the power factor compensation
Electrical appliances mostly electromagnetic structure, requires a lot of excitation power, resulting in the user's power factor are slow and low, generally about 0.7 or so. Excitation power - lag phase reactive power flow in the distribution network, not only takes up distribution network capacity, resulting in unnecessary losses, and cause the user voltage decreases. Phase compensation is based on a phase of reactive power compensation equipment (such as shunt capacitor) nearest the user or distribution network supplying the required lag phase reactive power flows in the distribution network to reduce reactive power, reduce network losses, improve voltage quality. China for large power users require the installation of reactive power compensation device, power factor compensation shall not be less than 0.9.
Third, the grid voltage adjustment
To ensure that electrical appliances are in good working voltage, avoid being with voltage fluctuations damage electrical equipment, power distribution grid voltage needs to be adjusted. Grid voltage adjustment methods: central regulator, regulating transformers and reactive power compensation regulator regulator.
1. Use of regional power plant or substation hub for central regulator
This measure is simple and economical, convenient, but it can only change the voltage level of the entire supply area, can not improve the voltage distribution. When the supply relatively broad geographic area, power distances disparity, the central regulator measures are often not take into account the region, there are trade-off shortcomings.
2 tone regulating transformers
Can compensate for the lack of central regulator means for regulating local. Regulating transformer OLTC transformers, series booster and induction regulator three. OLTC with induction regulator is generally used for a specific load point, the series booster is used to power lines.
The role of regulating transformer regulator power network by changing the reactive power flow to achieve. It is in itself not only produce reactive power, but also because of their need for excitation and consume reactive power. When the grid is insufficient reactive power, voltage regulator transformer no significant effect. Conversely, if too much regulating transformers installed, will increase the distribution grid reactive power consumption, low voltage level of the whole network, increasing network losses, reduce reactive power of capacitors in parallel, may cause serious vicious cycle trend.
3 reactive power compensation regulator
Because of the increased power grid reactive power, can play a role in improving the grid voltage. Installed in substation reactive power compensation device, can be applied to the packet switching approach for the implementation of central regulator supply area.
4 series capacitor compensation regulator
Series capacitor compensation may be used for local distribution grid regulator. Heavy lines in long distance, because the role of regulator through the line current flowing through the phase lag generated by the series capacitor voltage rises to achieve. Therefore, the heavier the load line, the lower the power factor, the role of regulator series capacitor compensation more remarkable. This regulator role in line with the load change, with self-adjusting function.
|
 |
|||
| 网站地图 |
