| Applications Surge reactive compensation devices in transmission system voltage and reactive power control | |
| datetime:2016-09-05 Hits:900 | |
| Large voltage fluctuation of the power system will not only affect the user's normal use of a variety of electrical equipment or life, etc., it will also affect the design of the insulation installed in the electric power system of a variety of electrical equipment, to stabilize the operation of the system, high efficiency operation obstacle. In order to play coupled to the electrical power system all electrical equipment, the normal function of electrical equipment must be carried out voltage and reactive power control. During voltage regulation, usually should be controlled reactive power, this paper describes several reactive power adjustment method, and analyzed the comparative characteristics of several methods, defects, as well as automatic reactive compensation devices in power system applications generated benefits. Voltage power system as the load changes while changing power generation capacity. Such as voltage fluctuation is large, not only will affect the normal life of the user or use a variety of electrical equipment, etc., will also affect the design of the insulation installed in the electric power system of a variety of electrical equipment, so that the stable operation of the system, high efficiency run an obstacle. So in order to play the normal function coupled to the electrical power system all electrical equipment, electrical equipment, and seek stability of the system, high efficiency operation, the need for voltage and reactive power control. First, the traditional reactive power compensation device 1, in order to ensure the system bus voltage constant, to change the reactive power compensation capacity, just by putting a group or several groups of capacitors that change the capacitance value of the access system. China is currently the substation reactive compensation devices are usually manually switching capacitor is generally one bus cast a bank of capacitors, and the capacity of the capacitor are large, when the compensation is greater than the capacity of the capacitor substation reactive power shortfall, put on the capacitor will complement appeared, not less investment will complement. Main problems associated with traditional complementary equipment: (1) a single set of compensation capacity, reactive power compensation is not fine. (2) Less often appeared complement and supplement, often in idle equipment, low capacity utilization, reactive power compensation is not satisfactory, wasted investment. (3) when switching capacitor banks, there is a big inrush current and over-voltage operation, likely to cause damage to the switches and capacitors. 2, packet switching automatic reactive power compensation device Later, people in order to meet the requirements of multi-level compensation, automatic packet switching reactive power compensation device, the usual practice is to a large-capacity capacitor bank into multiple small-capacity capacitor bank switching switch selection of vacuum contactors, general contact electrical life of up to 100,000 times, can meet the needs of frequent operation. Shortcomings: The number of groups (1) split, the more need to vacuum contactors, reactors, more discharge coil, high cost, large area, it is generally in the design, up to split into four groups, and reactors multi-core dry-type reactors, only for indoor arrangements. (2) In this way compensation only to a certain extent implemented compensation capacity, or to change the capacitance value of the access system by switching operation can not be a better solution reactive power compensation fine. Both reactive power compensation device, whether it is by a large capacitor bank switching circuit breakers, contactors or by packet switching small capacitors are used to change the capacitance value of the access system by switching division, there must be switching Japan surge over-voltage operation and other issues, low reliability of the apparatus, in particular switches and capacitors and other components high failure rate. There are no merits and make up less reactive problem. Second, the regulator Reactive Power substation reactive power automatic compensation device According to the principles of electrical engineering, no output capacitor bank capacitance value is proportional to the reactive power and capacitor bank, proportional to the square of the terminal voltage of the capacitor bank, namely Q = wCU2. Surge Reactive Power substation reactive power automatic compensation device is based on the output capacitor bank Reactive proportional to the square of the terminal voltage of the capacitor bank of the development. 1, the device has the following characteristics: (1) more reactive power compensation series, fine compensation capacitor bank utilization. Suppose each substation bus fitted on each of the devices in the substation breakdown is running, it can be divided into multi-level compensation. This traditional reactive power compensation device is almost impossible to achieve. (2) using the formula auto-load regulator, reactive power compensation capacitor bank uninterruptible power adjustment process, the regulator only a few hundred volts between each stall, the adjustment process without over-voltage and surge problems. (3) long-term work under rated capacitor voltage, a current flowing through the capacitor is less than the rated current, and no inrush current and over-voltage shock, the capacitor so long life, high reliability, complete sets of equipment. (4) If the substation power load harmonic current is very small, you can also remove the reactor, the regulator itself can inhibit the inrush current leakage reactance of complete sets of equipment in the circuit breaker when the input. (5) a small number of elements, the reactor can be dry air core reactor (outdoor placement), it can also be used iron core reactor (indoor place) dry. (6) for the transformation of the old station. For the transformation of the old station, the device just in between the circuit breaker and capacitor banks traditional reactive power compensation device is a series regulator, the existing circuit breakers, chokes, capacitors, discharge coil and so can continue to use . Grade reactive power compensation (7) it is very suitable for high voltage (6kV, 10kV, 35kV) under. 35kV frequent operation switchable high price, large volume, the device can be used to avoid these problems. Third, the installation of surge-type automatic reactive power compensation device after generation of benefits Benefits arising after installation regulated pressure automatic reactive power compensation device is mainly reflected in the following aspects: First: a stable system voltage, transformer tap to reduce the operating frequency. Surge-free power automatic compensation device design principle is to first consider the voltage qualified, qualified after considering reactive power, before adjusting the main transformer tap held in place, is about the reference voltage is set within a range of suitably qualified, when the load voltage is lower than the eligibility criteria lead to an increase, it becomes increasingly automatic reactive power output, raise the bus voltage to the acceptable range; when the load is reduced bus voltage is higher than the eligibility criteria, reducing the amount of reactive power output will be reduced to the bus voltage Eligible range; when the voltage is within the acceptable range, according to the reactive power factor requirements to meet the shortfall. Second: to extend the life of system and user equipment, to maintain a high utilization rate of the capacitor. Control Principle Surge automatic reactive compensation device type is a group of large-capacity reactive power compensation capacitor connected to the output side and a flat-load voltage regulation of self-coupling transformer, autotransformer primary side connected to the capacitor switchgear below, through a plurality of gears transformer regulation, changing the voltage on the capacitor, thereby changing the amount of reactive power. Since the capacitance by switching load tap mode, the capacitor will not appear in the process of power between multiple files, voltage regulation during the transition by transition resistance, voltage switched capacitor network is not disconnected, the power supply phase does not exist voltage forming superposition problem, the adjustment process will not have an impact on the compensation system and the power grid and other electrical appliances. And most of the time working at a lower capacitor voltage capacitor can guarantee security, greatly extending its life. Tap-long mechanical life, fast switching operation to meet the frequent fast switching requirements. Regulating device under control of high voltage reactive power compensation automatic control system according to changes in inductive reactive power, dynamically adjusting the voltage across the capacitor, dynamic reactive power supplied by the special regulating transformer. High pressure by a computer reactive power compensation automatic control device, through real-time collection grid voltage, current, power factor, analyze trends load, reactive power system harmonic content, voltage fluctuation system, regulating the use of fuzzy control technology on-load tap-changer, dynamic compensation optimization, and achieve reactive power compensation capacity with the changes in the system load reactive capacity automatic tracking purposes. Third: to achieve unmanned substation, saving human resources. Surge-free power automatic compensation device using automatic control, switching equipment, capacity converted by the controller completely automatic control, no need to artificially control the switching capacitor, saving human resources. Fourth: the compensation is more sophisticated, reduce system losses. 1, line loss reduction: And current proportional to the square of line loss, the greater the current power lines, the greater the line loss, if we do not change under the premise of power transmission capacity and improve the power factor, can effectively reduce the power lines the current size, but also can effectively reduce line losses. 2, the transformer loss reduction: When the reactive current flowing through the transformer, the transformer's own impedance characteristics will produce power loss. Also put into use SVQR device, can realize reactive power compensation on the spot, to reduce the current flowing through the transformer, the transformer losses are reduced accordingly. IV Summary Use regulated pressure automatic reactive power compensation device, the voltage level of qualification and stability has been significantly improved, so that the voltage across various grid spaces configuration, reactive power control equipment to achieve coordinated operation. Ensure the security of power supply systems and electrical equipment, normal and stable operation, reduce the loss of power transmission systems, to achieve the purpose of energy saving. |
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