TBBFX10 (6) high voltage shunt capacitor box type compensation device
1. Overview
TBBFX type high voltage shunt capacitor box type compensation complete set device (hereinafter referred to as the device) is a new type of shunt capacitor compensation complete set device developed by our company according to the box type variable shape on the basis of tbbf. It is divided into equal or unequal capacity groups according to the capacitor, and adopts vacuum contactor or vacuum circuit breaker and voltage and reactive power automatic control device to realize automatic switching and control of capacitor bank The new device can automatically adjust bus voltage, compensate reactive power, improve voltage qualification rate and power factor, and has the characteristics of safety, reliability, convenience and flexibility, making full use of capacitor capacity and improving efficiency.
According to the total amount of reactive power to be compensated, the device can be automatically switched on and off as a whole group, and several sub units with equal or unequal capacity can be designed according to the requirements and needs. The voltage and reactive power of the power grid are detected by the automatic switching device, and the purpose of automatic switching capacitor is achieved by reasonable control and protection.
The device is suitable for 220kV and below substations in power plants, electric power bureaus and large factories and mines. In the 6-10KV power supply system, the reactive power is automatically compensated and controlled. The target cos φ or QC value set by the user can be achieved by using the switching function of capacitor, so that the system voltage and reactive power are in the best state automatically.
2. Environmental conditions for use
2.1 outdoor use;
2.2 the altitude shall not exceed 2000m;
2.3 the ambient air temperature is - 25 ~ 40;
2.4 relative humidity: daily average no more than 95%, monthly average no more than 90%;
2.5 the surrounding air is free from corrosive gas, steam and other serious pollution, no combustible gas, no fire, no explosion danger.
2.6 places without frequent violent vibration.
2.7 the network or bus voltage power supply side of the installation point shall be free from large waveform distortion and the influence of high-order harmonic source. The voltage waveform distortion rate and harmonic content shall not exceed the provisions of GB / T14549-93 "voltage quality, public power grid harmonics".
3. Structural features
TBBFX type high voltage shunt capacitor device is of box type structure. The capacitor banks in the box are arranged in order of multi cabinet assembly like prefabricated substation. The whole cabinet is made of high-quality cold-rolled steel plate bending welding or aluminum zinc coating plate bending assembly. The box body is made of high-quality composite color plate or steel plate, which has good heat insulation performance and water-proof effect. There are single or double doors in the front and back of the box, the top, bottom and side sealing plates, and the ventilation and heat dissipation windows are set up, which has good heat dissipation and ventilation effect. An instrument room is set on the top of the cabinet in the box to arrange and arrange the relay protection device of the unit cabinet. The device is mainly composed of a single shunt capacitor, equipped with a single capacitor protection fuse, discharge coil, zinc oxide arrester and CKS dry-type series reactor (the reactor can also be peripheral), as well as reliable no re ignition, no bounce vacuum contactor (or vacuum circuit breaker and sulfur hexafluoride circuit breaker) as the grouping automatic switching equipment of the shunt capacitor bank Copper bar tin plating is adopted for connecting bus bar, and its shape and structure are shown in Fig. 1 and Fig. 2. The whole device is equipped with indication instrument and relay protection or microcomputer protection unit according to unit cabinet. The device has the following characteristics:
3.1 the shunt capacitor banks with equal or unequal capacity can flexibly realize the automatic control of reactive power with reasonable compensation;
3.2 simple structure, miniaturization of products, one cabinet, one control unit, or multi cabinet control unit; it can be divided into 6 units at most, and the compensation capacitance can be large or small, beautiful appearance, convenient and flexible selection, and low investment;
3.3 due to the group automatic switching, the utilization rate of capacitor is high;
3.4 the front switch cabinet adopts the combination of microcomputer protection measurement and control and automatic switching device of capacitor bank, with full protection and control function and high automation degree;
3.5 automatic and manual operation, flexible operation, simple control, safe and reliable.
3.6 it has RS232 or RS485 serial communication interface, which can be connected with other monitoring equipment in the substation to form the integrated automation system of the substation, which can meet the requirements of various operation and management modes such as unattended or less attended, centralized control and so on.
3.7 it has over temperature and over-voltage protection alarm and internal and external fault locking function;
3.8 high protection performance, with incoming line isolation and grounding interlock, when the device is stopped, the neutral point and phase line can be grounded at the same time; it has good five prevention locking protection performance.
3.9 the products meet the requirements of GB 50227-1995 "code for design of shunt capacitor device", JB / T7111-1993 "high voltage shunt capacitor device" and DL / t604-1996 "technical conditions for ordering high voltage shunt capacitor device" and other standards and relevant technical standards.
4. Inspection, adjustment and test before operation of complete set of equipment
4.1 pre operation inspection
4.1.1 the preparation and inspection of high voltage switch cabinet before operation shall be in accordance with the relevant requirements of its installation and operation manual.
4.1.2 the inspection and installation shall meet the requirements of Chapter 5 and Chapter 7. The automatic switching part shall be carried out according to the requirements of its automatic control manual.
4.1.3 the outgoing line end and insulator shall be clean without paint and damage, and there shall be no forgotten tools and equipment on the equipment.
4.1.4 the bus bar, spray step-by-step fuse, etc. shall be connected correctly and properly. The lead wire and indicator board shall face outward and shall not be reversed. The distance between the live part and the grounding part shall be ensured. The distance between the live parts of different phases and the main grounding frame shall be greater than the requirements of relevant standards.
4.1.5 the site should be clean and tidy, the grounding switch should be opened, and the temporary grounding wire should be removed.
4.1.6 check whether the setting value of the protection relay meets the requirements. See 8.2 for the setting value.
4.1.7 close and lock the door to prevent anyone from approaching the live part.
4.1.8 check that all interlocking locks are reliable to ensure safe and reliable operation of the device.
4.2 relay protection adjustment
4.2.1 it is necessary to ensure that all protective relays are intact and their action range shall be consistent with the drawings.
4.2.2 the over-voltage protection relay is set to 1.1 times the rated voltage of the device and acts with a delay of 0-60 s;
4.2.3 the undervoltage protection relay operates at 60% of the rated voltage of the device;
4.2.4 the over-current relay shall not operate under 1.3 times of the rated current of the capacitor bank. It shall be set at 1.6 times of the rated current of the capacitor bank and act with a delay of 0.5 seconds.
4.2.5 the over-current quick break protection relay is set at 5 times the rated current of the device, and the time limit is 0.15s.
4.2.6 the double star shaped neutral line unbalanced current protection relay is set to operate for 0.2-0.5 seconds when the breakdown time delay of some series components in a single capacitor is set. The reliability coefficient and sensitivity coefficient are 1.5 and 1.5 respectively.
4.2.7 the neutral line unbalanced current quick break protection relay is set at 3-4 times of the corresponding unbalanced delay protection setting value, with a time limit of 0.2S.
4.2.8 single star open delta zero sequence voltage protection relay is set to delay when some series components inside a single capacitor are broken down
2-0.5 seconds. The reliability coefficient and sensitivity coefficient are 1.5 and 1.5 respectively.
4.2.9 the setting value of zero sequence voltage quick break protection is 4-8 times of the setting value of zero sequence voltage delay protection.
4.3 test
4.3.1 relay protection action characteristic test: when no high-voltage power supply is connected and various fault signals are input into the secondary circuit, the microcomputer protection relay shall be able to operate normally, and the high-voltage circuit breaker shall be able to switch normally. In order to avoid too many switching times of high voltage circuit breaker, small bus fuse can be removed. During the test, the secondary wiring of voltage transformer should be removed to prevent high voltage reverse transmission.
4.3.2 one minute test of applying rated voltage: confirm that the equipment and installation have the conditions for voltage application, apply the rated voltage for one minute, record the current value of each phase, and observe whether the equipment has abnormal phenomena. Then cut off the power supply, operate according to the operating procedures, close the grounding switch, and then check the equipment.
4.3.3 fault protection test for internal components of capacitor: it shall be conducted after completing the tests in 8.3.1 and 8.3.2. The number of shunt capacitors in each phase and each arm is increased and reduced in turn, and the failure of internal components of capacitor and fuse fusing are simulated equivalently. Whether the complete set of devices can protect correctly in case of failure is evaluated. The action value of relay protection in each fault state is measured in the test.
4.3.4 check the function of automatic reactive power controller, the on-off performance of group capacitor switching switch and its secondary wiring. Without high-voltage power supply, disconnect the fuse for single over-current protection, and switch on and off the switching equipment in each capacitor cabinet through the manual mode of reactive power automatic controller. Then set the transformation ratio of the current transformer and the delay time of group switching. The set value of the transformation ratio of the current transformer should be consistent with that of the total current transformer in the switch cabinet; the setting value of the delay time should not be less than 5 minutes. Before the device is put into operation, other parameters of the controller are set automatically through the programmable menu of the controller.
4.3.5 if the conditions are met, the inrush current and switching overvoltage tests of the complete set of devices shall be conducted, and the corresponding waveforms shall be recorded.
5. Operation, maintenance and overhaul
5.1 when switching the capacitor bank automatically, according to the schematic diagram, first turn on the control power supply, turn the transfer switch to the automatic position, and then operate the controller to enter the automatic switching state. When manual switching is required, turn the transfer switch to the manual position, and then turn the knobs one by one to the corresponding gear or press the corresponding buttons to enter the manual control operation.
5.2 the operator on duty shall make a detailed record of the operation. Within 24 hours after the start of operation, the bus voltage and the current of each phase of the device should be observed frequently, and the capacitor should be checked when the load is light.
5.3 it is recommended to observe the operation of all parts of the complete set of equipment once every hour. At least once every three months, the surface of each bushing, the shell and cabinet frame of each electrical appliance shall be cleaned to avoid accidents caused by dust, dirt and mixed humidity. Check whether the electrical connection is in good contact and whether the nut is loose. If any problem is found, timely handle it to avoid early damage of capacitor or equipment accident caused by partial corona discharge.
5.4 according to the reactive energy meter and ammeter on the high voltage switch cabinet, check the capacity and load of the device, and the action of the protection relay is OK
Observe through signal relay and indicator light. If the device is in use, the relay protection action output to trip, and before finding out the reason and handling it correctly, it is not allowed to force reclosing.
5.5 when the transformer or shunt reactor is in charge, the transformer or shunt reactor shall be put into operation first, and then the complete set of compensation device shall be put into operation. When the transformer or shunt reactor is cut off, the reverse procedure shall be followed to avoid current resonance damage between the complete compensation device and the system.
5.6 if the capacitor is damaged and replaced with a spare part or a new capacitor, it should be noted that the capacity of the capacitor to be replaced is the same as that of the replaced capacitor as far as possible, meeting the requirements of 7.3.2.
5.7 preventive inspection and test for main components of the complete set of equipment, such as capacitance of capacitor, series reactor and mutual inductor
Insulation resistance, oil level, oil pressure, etc., should be carried out regularly according to the corresponding use and maintenance instructions. The operation and maintenance of high voltage switch cabinet shall be carried out according to the requirements of its installation and operation manual.
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