Power Factor Controller, also known as:Reactive power compensation controller
1 Application. Reactive power compensation equipment is used to reduce the unnecessary load caused by the induced current to the power distribution equipment and reduce the overhead caused by reactive power loss. The main component of this type of device is the power factor controller, which automatically turns the capacitor step bank on and off to compensate for the induced current.
2 How it works.
Single-phase electronic measurement systems capture the reactive and active power components of the network through current and voltage paths. The power factor controller calculates the necessary reactive power from the current in the outer conductor and the voltage difference between the two outer conductors in order to achieve the set power factor. If there is a phase shift, the capacitor step bank is switched on or off via the output. Here, the switching operation of the capacitor is distinguished by means of a protective contactor or a semiconductor switch. On the other hand, the contactor using capacitors can be optimally regulated, which means that the power factor controller can achieve the target value COS with less operation. The virtually delay-free operation of the semiconductor switch produces a capacitive output that compensates for each phase difference.
3. Control of ventilation and heat dissipation equipment.
The output of a relay can be used to control the ventilation and heat dissipation unit, where the upper and lower temperature limits can be programmed.
4. Overheat disconnect protection.
The thermal disconnect protection measures can disconnect the connected capacitor step group to reduce the internal temperature and protect the capacitor. Here the upper and lower temperature limits and intermittent times can be programmed.
5 Measurements. It is actually a meter that measures the power factor, and there are several ways to measure it, which are:
1. The power factor is directly measured through the waveform of voltage and current, which is simple, but the adaptability is poor, and the error is large when encountering harmonics.
2. Convert the success rate factor by measuring the reactive current, which is also simple, but the accuracy is poor and it cannot cope with harmonics.
3. Convert the power factor by measuring the active power and reactive power, this method is currently popular, with high precision and good adaptability to harmonics, but the technology is more complex, the software work preparation requirements are very high, and the technology is easy to cause problems if the test is not passed.
After the power factor of the load is measured, the capacitor can be put in or removed, that is, the reactive power of the load can be compensated with the appropriate capacitance. At this time, the controller gives a put in or cut signal, and it's done.
6. The use environment of the reactive power compensation controller.
1. The working environment temperature is -25 +65
2. The relative humidity of the air is 95[%].
3. The altitude is 2500m
4. The installation environment is clean and free of conductive dust.
5. Installation method: indoor screen type, outdoor box type.
7. Classification of reactive power compensation controllers.
The reactive power compensation controller is divided into high-voltage reactive power compensation controller and low-voltage reactive power compensation controller according to the working voltage.
1. High-voltage controller: generally suitable for power frequency transmission and distribution system or 6 10kV urban network and rural power grid lines
A, capacitance reactive power automatic compensation controller (i.e. QC, capacitance adjustment only).
b, Voltage Reactive Power Automatic Compensation Controller (i.e. VQC).
c. Voltage regulation type reactive power automatic compensation controller (developed for voltage regulation type compensation device).
d, high-voltage line compensation controller (applicable to urban grid, rural network line).
2. Low-voltage controller: suitable for 660V and below distribution lines;
a. Three-phase co-compensation controller: suitable for the occasion of basic balance of three-phase load;
b. Three-phase co-compensation + single-phase sub-compensation integrated controller: suitable for three-phase load unbalanced occasions.
8. The protection function of the reactive power compensation controller.
The overload of the capacitor is caused by too high voltage or too large harmonics, so it is necessary to design the overvoltage protection function in the controller. If the ability allows, the voltage harmonic detection function should be designed in the controller, because the fundamental cause of the capacitor harmonic overload is voltage distortion, and the detection of voltage harmonics can realize the harmonic overload protection of the capacitor. With overvoltage protection and harmonic overload protection, thermal relays can be eliminated. It not only saves volume and cost, but also reduces the point of failure.
9. Selection of reactive power compensation controller.
1. For the situation that the load of the power grid does not fluctuate much, and the three-phase load is basically balanced, and only the goal is to improve the power factor, in order to reduce the cost of equipment, a simple reactive power compensation controller with a single function and easy operation can be selected. The control physical quantity can not be strictly required, and the reactive power, reactive current or power factor can be used as the control physical quantity, and the compound control physical quantity can also be used. The switching method can adopt a simpler cyclic switching mode. In this way, it can not only achieve a better reactive power compensation effect, but also reduce the production and manufacturing cost of the equipment, and at the same time, the equipment is simple to operate and easy to maintain.
2. For the situation that the load of the power grid fluctuates frequently, the gap between the maximum load and the minimum load is large, but the three-phase load is basically balanced, it is advisable to choose a controller with better performance. For example, reactive current or reactive power should be selected as the control physical quantity, and the input threshold and excision threshold should be set separately to prevent switching**, and protection functions such as overvoltage and undercurrent should also be provided. It is best to use a programmable cutting method"Encoding + Looping"Switching mode to ensure that the controller can quickly and accurately dynamically track and compensate for changes in reactive power.
3. When the load of the power grid fluctuates frequently, the gap between the maximum load and the minimum load is large, and the three-phase load is seriously unbalanced, the selection of the controller puts forward higher requirements, which should have"Splitting phase + balancing"Compound switching function.
4. In order to cooperate with the implementation of power grid automation, while improving the power factor, it is also required to be able to monitor the various operating parameters of the power grid in real time, in this case, it is necessary to select the reactive power compensation controller with comprehensive test function (distribution synthesis, constitute an anti-harmonic reactive power compensation control device, so as to operate reliably under the condition of more serious harmonics, and achieve satisfactory compensation effect.
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Zhejiang Yishuo Electric Co., Ltd. is a high-tech company specializing in R&D, design, production, sales and service of low-voltage power capacitors, smart capacitors, reactors, reactive power compensation controllers, and reactive power compensation devices.
The company adheres to the tenet of "taking science and technology as the driving force and seeking development by quality", and is committed to building a leading brand of smart grid professional services. The company adheres to the tenet of "taking science and technology as the driving force and seeking development by quality", and is committed to building a leading brand of smart grid professional services.
The company has a high-level R&D management team, integrating R&D, production, sales and service, focusing on intelligent reactive power compensation, harmonic control, energy saving and power quality management and other high-tech industries of power automation.
Over the years, we have adhered to the mission of "making products intelligent and services intimate". In line with a high sense of responsibility to the society and users, Yishuo Electric adheres to the road of specialization, continues to innovate and transcend, and strives to make greater contributions to China's smart grid power automation