The construction of distribution automation of smart grids is accelerating. First of all, a large number of online switch cabinets must be transformed. The early switch cabinet design is also based on manual operation. The main task of the equipment upgrade is to install a drive motor on the operating mechanism, which is upgraded to electric button operation by relying on manual lever operation.
Switch cabinets are divided into circuit breaker cabinets, recloser cabinets, incoming cabinets, outgoing cabinets, load switch cabinets according to different uses and installation locations. Rely on the protection of the fuse tube.
1. Classification control mechanism of electric operating mechanism
The operating mechanism of the switch cabinet is divided into four types.
1. Circuit breaker mechanism
It can be combined into an extended switchgear in the form of a unit module. According to the original design, the overcurrent release is adopted. The setting standards are rated current 630A and 1250A. The opening and closing of the contacts is realized by the release power of the mechanical energy storage device. The main working principle is to use torsion spring linkage energy storage, and use the stored energy spring as the power to realize the opening and closing operation of the circuit breaker. The opening operation includes the opening electromagnet, the overcurrent trip electromagnet and the manual button operation. Kind.
2. Circuit breaker/recloser mechanism
The structure of the recloser is composed of an arc extinguishing chamber, an operating mechanism, and a control system. The recloser can perform a secondary operation of breaking/closing after the primary energy storage. There are two ways of driving the contact: permanent magnet and spring. Rely on the electronic control system to realize quick break and reclose.
The function of the recloser is to cooperate with other high-voltage electrical appliances, through its circuit breaking, reclose operation sequence, reset and lock, identify the location of the fault, and minimize the power outage area limit, while the circuit breaker is only used to open the short circuit fault and the line power outage area Big. The recloser has its own control equipment, and a self-contained system of detection, control, and operation can automatically and quickly close and restore line power supply under system intervention.
3. Load switch with grounding knife structure
Electric operation and manual operation are on the same drive shaft. When the manual lever is inserted into the operation hole, the transfer clutch is pressed for manual operation. The accurate torque of opening and closing positioning is greater than 80Nm.
4. Fuse structure
The fuse is the simplest protective electrical appliance. It is cheap and suitable for areas where the electrical load is not large. It allows the load current to pass within the specified standards. When electrical equipment is overloaded and short-circuit current occurs, it will quickly automatically fuse and cut off the power supply line. Commonly used are the drop-out type of outdoor overhead lines and the embedded type of indoor switch cabinets.
2. The control mechanism of the electric operating mechanism
In the circuit breaker control, after the energy storage is in place, there is also an anti-bounce control circuit. The control circuit should be able to reflect the position of the circuit breaker in time and the integrity of the tripping and closing circuit. In order to ensure that each step of the circuit breaker is safe and reliable, a variety of blocking measures must be installed in the control loop. When the conditions are not met, the operation of the circuit breaker is prohibited. When the operating system of the circuit breaker is abnormal, the opening and closing circuits are blocked. When the pressure of the hydraulic/pneumatic operating mechanism is too high or too low, the spring of the spring operating mechanism is not stored energy, the SF6 pressure of the SF6 circuit breaker is low, etc., these will disconnect the normally closed contacts connected in series in the tripping and closing circuits. The circuit breaker is allowed to open and close.
3. New multifunctional electric operation controller
1. The controller is the core unit of the intelligent ring network cabinet. According to the predetermined sequence, change the wiring of the main circuit or the control circuit and change the direction of the current in the circuit to control the starting, speed regulation, braking and reverse master device of the motor.
2. The main functions and functions of the controller
(1) The controller needs to receive and recognize higher-level commands: the program of the control center can send a variety of different commands to the controller, and the device controller should be able to receive and recognize these commands. The controller continuously sends electronic inquiries to various sensors of the equipment, and replies to the superiors with the execution results.
(2) The controller is the control component, and the peripheral device is the execution component relative to the controller. One connection between the control part and the execution part is through the control line.
(3) The control component sends various control commands to the execution component through the control line. Another connection between the control part and the execution part is feedback information. The execution component reflects the operation situation to the control component through the feedback line, so that the control component issues a new action command according to the status of the execution component, also called "status test".
(4) The controller is divided into one-way controller and two-way controller according to the function of each drive motor.
The controller also needs to be equipped with motor constant current control technology: the motor starting torsion current is matched with the dynamic running current, which improves the motor's starting torque balance, and can protect the motor and the overall equipment when the mechanical gear fault torque increases. Therefore, the controller must have a suitable selection of current control components, which can be applied to any type of motor, and has a fairly safe control effect. It is no longer necessary to match and improve the general adaptability of the electric vehicle controller, so that the electric vehicle motor and the controller , No need for on-site equipment matching, easy to install and use.
(6) As long as the controller automatically detects the interface status related to it, such as external switch signals, etc., once a failure occurs, the controller automatically implements protection to fully ensure the safety of the equipment, and the protection status of the controller will automatically recover after the fault is removed .
(7) The controller shall have the integration of automatic/manual operation functions, and be configured flexibly according to different use environments. The automatic transfer switch controller is an intelligent dual-function switching system. The electrical interlock of the controller cooperates with the mechanical interlock to ensure the automatic adjustment of the controller parameters.
(8) Control function
Load switch opening/closing: After receiving the opening and closing command, it starts to output a current of no more than 24v 10A to the motor, and the motor is driven forward and reverse.
Breaker tripping and opening/closing: The circuit breaker releases energy in the energy storage structure to push the mechanism to open/close.
The auxiliary contact of the mechanism is interlocked with the grounding station; interlocked with the cable box door; interlocked with the air pressure detection device:
Any circuit operation of blocking contact grounding is prohibited to close/open and trip.
3. The control circuit of the circuit breaker is the most basic secondary circuit
The SZLL-6160 distribution network safety controller product integrates high efficiency, reliability, safety, flexibility, and compactness, and can adapt to various harsh environments. The compact and modular design can meet the needs of future switchgear upgrades and expansions. The product's unique electronic and mechanical interlocking design, torque drive constant current protection system, ensure the safety of operators, and can also deal with mechanical transmission failures in time.
(1) Control circuit optimization
(2) Convenient maintenance and operation and maintenance
(3) Strong versatility, adapting to different standards of American Standard, British Standard, European Standard and National Standard,
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