HYHXB intelligent arc suppression comprehensive protection cabinet
1 Overview
The intelligent arc suppression comprehensive protection cabinet produced by our company has the functions of arc suppression, harmonic suppression, line selection and overvoltage protection, and the corresponding functions can be selected according to the needs. It is suitable for 3~35 kV three-phase indirectly grounded power system to limit various overvoltages, arc grounding overvoltages, resonance overvoltages, and operating overvoltages to improve the safety of power grid operation and power supply reliability.
2. Scope of application
★Suitable for 3～35 kV medium voltage power system;
★Suitable for three-phase indirectly grounded power systems such as neutral point ungrounded system and neutral point grounded through arc suppression coil or neutral point grounded through high resistance;
★It is not only suitable for power grids based on cable lines or hybrid power grids of cables and overhead lines, but also for power grids based on overhead lines.
3. Basic functions
★When a single-phase grounding fault occurs in the system, the faulty phase can be directly grounded in about 30ms.
★When a PT disconnection fault occurs, the device outputs a contact signal so that the user can block the relay protection that may cause a malfunction due to the PT disconnection.
★After the product operates, the panel displays the fault type (PT disconnection, metal grounding or arc grounding) and phase difference, and outputs passive switch contact signals at the same time. The product is equipped with RS485 interface, which can transmit data remotely according to the communication protocol provided by the user.
★The product can limit various overvoltages occurring between phases or between phases and ground to about 35 times.
★The voltage transformer in this product can provide voltage signals to metering instruments and relay protection, and can replace conventional PT cabinets.
★This product can be equipped with automatic line selection function according to user requirements, and can recall the information of ferroresonance in 20-fold system and 12-fold grounding information. This product selects the line based on the dual criteria of "relative amplitude" and "relative phase" of the zero-sequence current of the line, which overcomes the influence of the line selection caused by the change of the system operation mode, the resistance and the length of the line when grounding.
★This product can be configured to eliminate (de)resonance (vibration) function according to user requirements.
4. The role of main components
★High capacity three-phase combined over-voltage protector (KHYD)
It is a special high-capacity overvoltage protection device developed by our company, which plays a role in limiting the system overvoltage. It is different from the general zinc oxide arrester (MOA) in structure, and has the following advantages:
1. The discharge voltage value of the overvoltage protector is equal under various voltage waveforms, and the protection performance is not affected by the overvoltage waveform;
2. The instantaneous discharge value of the over-voltage protector is similar to the residual voltage, and there is no clipping, which is beneficial to protect the turn-to-turn insulation of winding-type equipment;
3. The overvoltage protector adopts four-star connection, which can greatly reduce the overvoltage between phases. Compared with conventional lightning arresters, the reliability of protection is greatly improved. The overvoltage protector is the first device in this product to limit various overvoltages, and the voltage is limited within a safe range before the contactor is activated.
★High-pressure vacuum quick contactor (JZ) with phase separation control
The high-pressure vacuum quick contactor can complete the opening and closing in 8~12ms. One end of the vacuum contactor is respectively connected to the bus bar, and the other end is directly grounded. During normal operation, the contactors are all in the disconnected state and closed under the control of the microcomputer controller ZK. The operation circuits of the vacuum contactors of each phase are mutually locked. When any one of the phases is closed to ground the busbar of that phase, any one of the other two phases will no longer act. The function of the contactor is to quickly change from unstable arc grounding to stable metallic direct grounding when arc grounding occurs in the system, thereby protecting the equipment from damage.
★Multifunctional microcomputer controller ZK (including voltage signal converter)
The controller ZK is the core control component of the device. It judges the fault phase and the fault type (PT disconnection, metal grounding and arc grounding) according to the Uao, Ubo, Uco, Uo signals provided by PT, according to the preset Way to control the high-pressure vacuum contactor. All the functions of the microcomputer controller are executed automatically, no manual operation is required, and the operation and maintenance are simple. The microcomputer controller adopts secondary power supply technology, which can resist all kinds of electromagnetic interference. All interfaces adopt optical/electrical isolation, which can eliminate the interference of power supply and primary system to the controller. The controller is also equipped with a Watchdog self-reset circuit to realize the device The automatic reset completely avoids all kinds of external electromagnetic interference. The microcomputer controller adopts dual processors as the processing unit, which can complete the comprehensive control of arc suppression, resonance elimination and line selection at the same time, and the speed is fast. And it also has the functions of voltage transformer high-voltage fuse fuse alarm and voltage transformer secondary voltage signal loop failure alarm. The microcomputer controller can measure the voltage of the system and display it in digital form. The microcomputer controller is equipped with RS485/232 communication interface, which can report system fault information and device working conditions to the control center. The microcomputer controller has a memory, which can save the system's fault information (including fault type/fault time and other information) for a long time, and the user can query the system's fault record as needed. The microcomputer controller has designed the line selection module, which can complete the multi-outlet line (32 loops per section of the bus) single-phase grounding line selection, using the original "vector steep change method" line selection principle, no matter what type of grounding occurs in the system, it can be accurate Select the grounding circuit.
★ High-voltage current-limiting fuse assembly FUR
It is the back protection device of the entire product, which can prevent misjudgment caused by miswiring or product failure and then cause a short circuit between phases. It has the following functions:
1. The breaking capacity is large, up to 63kA; the breaking is fast, and the breaking time is generally 1~2ms;
2. The current limiting effect is good, and the fault phase current can be limited to less than 1/5 of the maximum short-circuit impulse current;
3. The breaking arc voltage is low, the arc voltage is very low during the fuse breaking process, and when used in a system with a voltage lower than the rated voltage, the arc voltage will be further reduced, so the 12kV fuse can be used in the 7.2kV system without Danger of damaging the insulation of the system. When a single-phase grounding occurs in the system, the voltage Ua at both ends of the open triangle of the voltage transformer PT immediately changes from a low potential to a high potential, so that the controller is put into operation. It can convert the three-phase high voltage signal of the system voltage transformer into a voltage signal (Ua Ub Uc) and a neutral point signal (Uo) that can be processed by the microcomputer controller.
★High voltage isolation switch GN
The connection point of the main busbar of the power grid is used for switching on and off during installation and maintenance of the device. It can also be changed to isolate the handcart according to the needs of the user.
★CT and ground current meter
When the device is in action, the grounding capacitance current of the system can be more accurately read through the grounding ammeter.
5. Product advantages
The product has fast action speed, which can move quickly within 30~40ms, which greatly shortens the duration of single-phase grounding arc;
After the product is activated, the arc can be extinguished immediately, and the arc grounding overvoltage can be effectively limited. After the product is activated, the 200A capacitive current is allowed to pass continuously for at least 2 hours. The user can handle the faulty circuit after the load transfer operation is completed. The protection function of the product is not affected by the scale of the grid and the operation mode;
This product uses the characteristic of maximum zero-sequence current sudden change in the fault line before and after the arc is extinguished for line selection, which can greatly improve the accuracy of line selection.
6. How the product works
When the system is in normal operation, the open delta voltage U△ is very small, the controller panel displays "Operation" and can display the voltage of each phase. When U△ changes from low level to high level, it indicates that the system is malfunctioning. At this time, the microcomputer controller ZK immediately starts the interrupt; according to whether the secondary output voltage of the PT exceeds the given value, the fault type and phase are judged:
If it is a single-phase PT disconnection fault, the fault phase and disconnection signal will be displayed on the product panel, and the passive switch contact signal will be output;
If it is a single-phase arc ground fault, the product panel displays the fault phase and grounding type signals, and at the same time sends a closing command to the fault phase vacuum contactor, and outputs the passive switch contact signal to directly ground the fault phase and ground the arc Since the arc voltage at both ends is immediately reduced to zero, the arc light is completely extinguished.
If it is used in a power grid with overhead lines as the mainstay, the vacuum contactor will automatically open after the product is activated for 5 seconds. If it is a transient ground fault, the system will return to normal. If it is a permanent ground fault, the vacuum contactor will be activated again after the product is activated. No more opening.
The working principle of the small current line selection device Before and after the grounding arc is extinguished, the magnitude and direction of the zero-sequence current of the non-faulty line are basically unchanged, while the zero-sequence current of the faulty line is changed from the grounding capacitance current of the whole system to the ground of the line Capacitive current, the direction changes by 180°, only the zero sequence current of the fault line changes the most before and after the arc is extinguished. Therefore, the small current line selection device designed by the principle of the maximum increment method can help the conventional line selection device to select when the arc is grounded. The problem of inaccurate line and even failure of line selection, and it is not affected by the arc coil.
7. Model and main technical parameters
8. Selection and design requirements
9. Structure, shape and installation dimensions
10. Use environmental conditions
Environment: Temperature: -40℃~+40℃, the monthly average relative humidity is not more than 90%
Altitude: ≤2000m, (a special design is required for more than 2000m)
Operating environment: there must be no explosive mixtures such as dust, gas, smoke, etc.
11. Packaging, transportation and storage
Generally, wooden boxes are used for packaging, and the cabinet base should be fixed on the bottom of the box.
It is not suitable for long-distance transportation on roads above Class III, and the packaging can be disassembled if necessary, and important parts should not be transported by road as far as possible.
When it is not used for a long time, it should be stored in a dry and ventilated warehouse. It is not suitable to be stored outdoors for a long time.
12. Installation, debugging and maintenance
The company is responsible for drawing design and parameter selection according to the user's requirements. After the equipment is assembled and debugged, it can be delivered only after being qualified by professional inspectors. If the user needs, the company can be responsible for on-site installation guidance and commissioning services, and the user provides necessary cooperation and assistance.
The equipment does not need maintenance and repair when it is working normally. Only after the product moves, check whether the fuse striker is popped out.
In the case that the user abides by the rules of storage and use, within 12 months from the date of installation and use, or within 18 months from the date of shipment, the product is damaged and cannot work normally due to quality reasons, and the manufacturer is free of charge. User replacement or repair.
The company implements lifelong maintenance of equipment and provides spare parts at preferential prices for a long time.
13. Ordering instructions
1. The user should provide the relevant rated voltage of the system and the maximum single-phase grounding capacitance current of the system as the basis for the design of this product.
2. The size of the cabinet can be finalized after being designed by our company's engineers and confirmed by the user's signature.
3. The user should clarify the functions of the device (including basic functions and optional functions), and if there are special requirements, they should be put forward when ordering.
4. If other additional accessories or spare parts are needed, the various names, specifications and quantities required should be indicated when ordering.
