Abstract: This paper KYN28A-12 high voltage switchgear in the operation and testing some of the problems that exist in the analysis, and for cable head, the second plug, the operation closed solenoid valve hole problems, an improved method.
glue stick Key words: KYN28A-12 High Voltage Switchgear cable head electromagnet.
KYN28A-12 also called armored away High Voltage Switchgear AC Metal-enclosed switchgear. By the cabinet and in the whole-mounted components can be extracted (ie Used) two major components, commonly known as the counters in the home. The structure is compact, small footprint, interchangeable Used to facilitate rapid processing failure, glue gun closed well, "Five Anti" feature complete, all equipment operations can be carried out under the door closed, safe and reliable operation, maintenance by the users. However, as part of the switchgear structure and components of quality and other reasons, resulting in operation and there are some problems during the test.
1 examine the electrical switch cabinet cable head problems.
1.1 Status and Problems.
Deqing Xiangongdianju associated procedures in the ground on KYN28A-12 High Voltage Switchgear provides switching of the operation were: verification of the correct line and then close the no-voltage grounding switch. As KYN28A-12 closed nature of high voltage switchgear, electrical inspection of the line in the open switchgear operation must be carried out after the next door. In fact the KYN28A-12 High Voltage Switchgear blocking performance with the electric shock, so that only after closing the earthing switch can only turn on the switch cabinet next door. So when the switch is changed by the running line maintenance (or switch and line maintenance), when people can not directly use the experience to run electric pen on the cable head to examine the electrical outlet. Operating personnel during the current co-Deqing Xiangongdianju ground before the switch operation, determine the line side is not charged: Used in the test position switch or maintenance position, the display of live line indicator does not light. If you meet these two conditions are that no power lines, you can close the ground switch. In fact, this mode of operation there is a big security risk, especially in the current 10kV power grid in the contact line more, if the live display is damaged, then in accordance with the present methods of operation, contact lines will be charged co-grounding switch may be serious consequences. In fact, this mode of operation in the "electrical safety regulations" in the electrical inspection is defined as an indirect way of testing indirect power is only used for 330kV and above experience in power electrical equipment. Therefore, for 10kV electrical equipment, should be done directly with the electric pen testing experience in electricity, charged nature of the display only as a reminder of the measures.
1.2 improvement.
Currently KYN28A-12 High Voltage Switchgear, under the closed door with the mechanical lock, when the grounding switch is closed, the next door to open. We can remove the existing mechanical locking device, using electromagnetic lock to replace the mechanical locking the lock, shown in Figure 1. Taken to an AC electromagnetic lock lighting power supply and power supply circuit in series in the live line display contacts. When the live line, the electric contacts disconnect the monitor, electromagnetic locks can not be exciting, so under the door closed; when the line power, the electric monitor contact closure, electromagnetic locks excitation, which can open the door for inspection under power.
Such improved use of existing conditions, do not make large changes can be implemented and strong. Power lines, you can open the door to the next inspection under the electric pen into his cabinet to carry out inspection on the first outlet cable for electricity, rejected that do not directly experience the previous mode of operation of electricity, preventing the possibility of grounding switch live together.
2 Test plug in the second issue.
2.1 Status and Problems.
According to rules of order, high-voltage electrical equipment to regular preventive testing. KYN28A-12 High Voltage Switchgear to switch overhaul when the operating personnel required to pull the switch outside the cabinet trolley, and close the switch cabinet door. At this point, the cabinet on the static contact is directly quoted from the 10kV bus, the state is charged. Therefore, to prevent electric shock from the point of view, work is generally not open the door, the work of the votes in the general security measures are also required to hang in the door, "stop, high risk" nameplate. The switch overhaul work, the need to switch to the second hand car plug and switch cabinet in the cabinet with the second plug to be connected to switch control system tests. After investigation, the current major maintenance personnel to plug in two ways with the second hand car second plug connector switch cabinet: one way is to open the door, push the switch Used to switch test location, directly connected to the second second plugs; second way is to use a dedicated connector, push the switch does not switch cabinet trolley case, the connection switch Used secondary plug and switch cabinet, this time the switch cabinet door can not close .
Analysis of the above two ways can be found there are certain security risks: The first way to switch Used to switch into the test position, this time from the switch and wiring equipment has been changed to overhaul the state line maintenance state, switch hands Car pushed to test position, switch Used static contact contact live close by the cabinet, and mechanical properties during the test switch, the switch contacts folder on both a short wiring test can not be ruled out if the cabinet static contact seal plate in the first case there is no reliable closure caused by the discharge of the situation. The second way is to use special connectors, switches, switch cabinet trolley can not advance to avoid the first approach of insecurity that may arise, this method is widely used in the present experiment. However, this approach makes the switch cabinet door is opened, and can not be reliably closed, and security measures linked to the switch cabinet door, "stop, high risk" does not meet the requirements of the nameplate, but actually in the cabinet as static contact first charged, although the cover plates separated living, but because the cabinet can not be reliably shut down, resulting in a collision repair personnel may be charged and the equipment hidden inside.
2.2 improvement.
Careful study of the structure KYN28A-12 high voltage switchboard, you can see in the cabinet door has a switch to open and close observation of storage instructions and the observation window, the moment, this observation window is fixed. The viewing window can be improved for activities outside the window open, active window switches installed in the door inside, only when the door opens only after the window from the inside to open the event. When the switch maintenance, the maintenance personnel to open the door and then open the activity window, the window of a dedicated connection plug inserted through the activities of the second plug in the cabinet and then locked the door. This would be the live parts and maintenance personnel through the door completely isolated, such improvements will not affect the overall layout and appearance switchgear, and gave work to bring a security overhaul.
3 grounding switch operating hole closed solenoid valve problem.
3.1 Status and Problems.
KYN28A-12 high voltage switchgear, the prevention measures to live together is a grounding switch operating hole grounding switch valve to achieve atresia. Earthing switch operating hole by mechanical and electrical interlock valve to open or close. Used when the switch is running (or hot standby) position, then switch Used directly by mechanical linkage of the grounding switch operating hole closed valve, so can not be inserted to operate the earthing switch operating handle; when the trolley is in cold standby switch ( or maintenance) position, the switch Used for locking out the role of mechanical valves, while not charged in the case of lines, live monitor contact closure, connected to solenoid circuit, grounding switch operation after excitation solenoid valve can open holes, which can the grounding switch operation.
KYN28A-12 High Voltage Switchgear change in the line maintenance operation by the switch (or switches and line maintenance) of the operation, a situation often occurs: Switches Used has been pulled to the cold standby (or maintenance) position, power passing through inspection , the line voltage side of the case are free, earth switch operation still can not open the valve hole, which can not be combined earthing switch operation. At this point the operator is only using the emergency unlock the tools to open the next door, the use of artificial means to mount ground state of completion of line maintenance. This approach makes the operation more complicated, increasing the operating time.
Place of operation, this situation can be found to cause grounding switch operating hole valve can not be opened because there are three main aspects: First, do not place the switch operating trolley (not yet reached the location or maintenance of cold standby position); second valve atresia electromagnet damage; third valve itself is a mechanical jam. Deqing Xiangongdianju operating personnel in the operation can not open the valve when the situation is basically due to damage caused by solenoid valve atresia, and repair that damage caused by the main magnet is a solenoid coil internal heat burn. When the switch cabinet is in line maintenance (or switch and line maintenance), the electric conduction monitor normally open contacts, which closed solenoid valve connected to power, the magnet excitation. In general, repair work will need to line maintenance equipment to maintain (or switch and line maintenance) a few hours, even days when the concentration of repair time, so locking solenoid valve in a few hours or days excitation state, the internal solenoid electricity and heating coil burned a long time.
3.2 improvement.
Solve the fundamental problem of damage to the solenoid is energized to minimize the magnet time, without increasing the difficulty of running the operating personnel. We can electromagnet excitation current loop, add a small button switch, and remove the original circuit in the AC-DC converter module (This module is to enable solenoid is not audible when the excitation), solenoid coil is AC and DC coils, you can not be replaced.
This small button switch can be installed in the ground next to the switch operating hole, press the small button to the lifting of the ground excitation solenoid valve switch is closed, open the trap door into a grounding switch operating handle, they can release the small button, then either earthing switch operation, and can cut off the magnet power supply, so as to achieve a double. In addition, when you press the small button, magnet excitation audible, you can prompt the operator solenoid normal circumstances, in order to prevent the operation of the valve solenoid jam and mistaken for damage problems.