WDBP Series Low-voltage Dynamic Reactive-power Automatic Compensation Cabinet
I Generalization
WDBP series of low-voltage reactive power compensation device (hereinafter referred to as the device) is a new reactive power compensation device developed by Worldwide Electric Group Co., Ltd. according to the technical requirements of the power system. It combined with years of practical experience in electric power automation equipment. The indispensable energy-saving equipment which can effectively compensate the reactive power, improve power quality, reduce losses is especially designed for the power sector and power users. At the same time, the device can provide operating data of distribution, which can provide a complete set of scientific basis for developing electricity running programs economically and safely
In the process of energy power transmission, the lack of reactive power will increase the total current, reduce the output of the transformer, increase active power loss of the power lines and system equipment, decrease the line terminal voltage. And for the power users, too much reactive power from the grid will not only decrease the grid quality, but also affect their own power and production. This will decrease the enterprises' benefit, or even incur a fine. Therefore, in order to reduce reactive power losses and avoid undue movement in the grid, enterprises must reactive power compensation.
This device adopts TRIAC zero-crossing switching technology, significantly reduce the inrush current of capacitor input, extend the life-span of the capacitor. String-type reactors can resist the harmonic components of the network to some extent. As for the control center, the reactive power compensation controller which adopts advanced control model support many switching models, such as encoding switching, equal capacity recycling switching, equal order switching, unequal capacity priority switching, unequal order switching etc. It has many protection functions such as over voltage, under voltage, over current and excellent anti-electromagnetic interference performance.
The device is suitable for 400V low voltage distribution network, can be widely used in companies such as outdoor desktop transformers, indoor power distribution room, box-type substation, and metallurgy, machinery, mines, railways, chemical etc. and low-voltage users can track compensation automatically
II Application and composition
2.1 Application
The device mainly adopts single-chip microprocessor technology and collect data of computing lines or distribution equipment, such as current, voltage, active, reactive and power factor. It can compensate reactive power automatically and monitor distribution by applying regional control principle, controlling switching power capacitors. It can control the capacitor switching correctly, make the transformer low-voltage three-phase balance and adjust power factor to the optimal state
It has two working ways: manual split-phase compensation and automatic compensation which convenient for users to test and operate. It can automatically select the best switching compensation according to manually entered compensation objectives. Take the life-span, compensation objectives and former compensation process of the field devices (such as self-healing capacitor, switching switch) into consideration. use the fuzzy control theory, select the best compensation scheme every time from the potential thousands of programs to achieve the best effect of reactive power compensation.
2.2 Product Composition
There are many typies of cabinet: GGD, GCK, GCS, MNS etc.
The main components in the cabinet are:
· Controller
· Knife fuse switch
· Air switch
· SCR switch component ensure the fast tracking and stability of reactive power compensation zero-crossing switching capacitance, has small impact of current (1.5 times of the rated current), life-span of switch, but the power consumption is large when the power flow (1.5W / A), more suitable for particularly frequent fluctuations (fluctuations more than 200 times per day).
· Reactor, used to control harmonic wave. Confirm the selected reactance ratio according to the background of the capacitor device access
· Over relay, over current protection.
· Capacitors, use dry BKMJ capacitors, high flow ability, with self-healing features, you can use
AKMJ series filter capacitor in special occasion
2.3 Instruction of product model
For example: WDBP—300 stand for total compensation 300 kvar
2.4 Compensation Capacity
Usually, the compensation capacity is 15 to 30% of transformer capacity, when users have special requirements of power factors, the compensation capacity can be chose to meet the required value of power factor
If the average active power of the maximum load of the power grid is Pp1, the power factor before compensation is cosj1, and after compensation is cosj2, the compensation capacity is available according to the following formula
QC==QP1 (1-1)
Or QC= (1-2)
III,Installation and commission
3.1 Installation
3.1.1 Installation environment
① Altitude should not exceed 2000 m
② The work conditions should meet technical temperature of the whole machine and the
atmospheric conditions
③ No dust, no dangerous explosion media, non-corrosive harmful gas, non-conductive particles, no serious mold, no strong electromagnetic interference around
④ There is no severe vibration and shock in the installation ground, and the vertical gradient is not more than 5 degrees
⑤ If indoor use, should choose the engine room where is good for ventilation and cooling
⑥ Alignment should be safe, convenient
3.1.2 Pre-installation check
The device is packed in a whole package, before installation, please check the components, accessories and quantity according to the shipping list, and check whether there is some appearance damage because of transport, the connection is loose or not, and whether there is some shake in the cabinet.
3.1.3 Installation
Users can select a good rack position according to the actual situation, mainly considering laid down lines, the convenience of inlet and outlet, and ventilation, there should be a passage less than 1 meter around, and please make sure that the horizontal inclination of the cabinet is less than 5 degrees. When the rack position is confirmed, check the connector, PCB, and fasteners inside is loose or fall off. Fix the rack with ground screws after confirmation.
As for household screen cabinets, we usually put the screen together, and wire through the cable channel. Current sample signal is selected from the measurement circuit.
When there is apparent damage display failure, please contact the manufacturer immediately and don't install and use.
3.1.4 Connection
① Connect the system three-phase voltage to the air switch input terminals.
② Connect the zero line to the zero line terminals of the block terminal
③ Connect the ground wire to the ground terminal
④ Make sure the ground wire is connected well, in case of personal safety.
⑤ Connect the current transformer lead-out wire to the corresponding terminal block.
⑥ Make sure the current transformer lead-out line is connected with the right polarity.
3.2 Debugging
When the air switch closed, the controller start to work, check three phase voltage, three phase current of the system. Calculate the system reactive power according to the amplitude between the voltage and current, and the phase difference between them. Compared the reactive power with the input threshold, the removal threshold, confirm the capacitor bank switching according to the system voltage amplitude
