KYN28A-12 to improve the high voltage switchboard

Abstract: This paper KYN28A-12 in the high voltage switchboard operations and experiments in a number of problems for analysis and for the first cable, plug the second operation hole closed solenoid valve problems and put forward ways to improve.
     Key words: KYN28A-12 high voltage switchboard cables in the first electromagnet

     KYN28A-12 high voltage switchboard, also known as exchange-sheathed away Switchgear. As a whole by the OEM and in-home can take part (that is, Handcart) of the two major components, commonly known as the home of cabinet. Its compact, small footprint, Handcart interchangeable, in order to deal with the rapid breakdown of the closure, "Anti-five" full-featured, all equipment can be operated in the state to close doors, safe and reliable operation, maintenance Welcomed by users. However, due to the switchboard and structure of some of the quality of components and other reasons, led to the operation and in the course of the trial, there are some problems.

     Cable 1 switch inside the first inspection of the electrical problem

     1.1 Status and Problems

     Deqing Xiangongdianju a point of order related to the high voltage switchboard KYN28A-12 grounding switch operation carried out: verify that the line voltage does not close after the grounding switch. Due to the high voltage switchboard KYN28A-12 closed for inspection of power lines to be operated under the counter in the switch to open doors before they could carry. In fact due to a high voltage switchboard KYN28A-12 closed against access to live parts of the performance, making only close the earth switch, the switch can open the doors under the counter. Therefore, when the switch from running to repair lines (lines or switches and maintenance), staff can not be run directly testing the use of electric cables in the first round of the pen to carry out electrical inspection. At present, Deqing Xiangongdianju co-operation in carrying out ground operations prior to the switch, side-line judge is not charged: Handcart switch in the location of the pilot or maintenance position, charged line of light is not bright display. At the same time if these two conditions are met, no power lines that can be closed grounding switch. Such practices in fact there is a big security risk, especially in the current 10kV power grid in the contact line more damage to the display if charged, in accordance with the current method of operation, the contact line may be charged co earth switch had not been serious consequences. In fact, this mode of operation in the "electrical safety point of order" is defined as an indirect way of testing electric, electric indirect way of testing only for 330kV and above electric power equipment testing. Therefore, the 10kV electrical equipment, electrical inspection should be done with total direct inspection of electricity, charged only as a prompt display of the nature of the measures.

     1.2 improvements

     At present, high voltage switchboard KYN28A-12, under the closed doors of the use of the machinery is closed, when the switch together on the ground, under the doors to open. We can dismantle the existing mechanical locking device, using electromagnetic lock to lock in place of mechanical lock, as shown in Figure 1. Electromagnetic lock the power to adopt the exchange of power lighting and power string circuit monitors charged into the line contact. When the live line, live off contact display, electromagnetic locks can not be exciting, so under the closed doors; when the power lines, live close contact display, electromagnetic lock excitation, which can open the doors for inspection under power, in Figure 2 Shown.

Figure 1 locking devices to improve

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Figure 2 electromagnetic lock circuit

Such improved use of existing conditions, do not need large changes can be implemented is strong. Power lines, you can open the doors to inspection under the power under the pen into a drawer, cable in the first round of inspection for electricity, not to abandon the kind of direct inspection prior to the operation of power and the prevention of a combined live on the earth switches.

   2 in the second test plug problems

     2.1 Status and Problems

     According to the rules of order, the high-voltage electrical equipment on a regular basis to carry out preventive tests. KYN28A-12 switches for high voltage switchboard overhaul, the staff running According to the request to switch to pull Handcart counter, and closed the doors in Switchgear. At this point, the inside of the static contact is quoted directly from the 10kV bus, live in a state. Therefore, to prevent the officers from the perspective of an electric shock, work in general can not open the doors, the work of the votes in the general security measures also put in the doors, "stop, high-risk" signs. The switch repair work, the need to switch the second-hand cars with plug switchgear cabinet in the second Plug and Play together in order to get control switch system test. After investigation, the current overhaul of the main staff to take two ways to achieve the second-hand cars and plug the second switch inside the connector plug: a way to open doors in the Handcart switch into the test position switch to a direct connection II Plug times; second approach is to use a dedicated connection plug, Handcart not switch into the switch cabinet, connect switches and switch inside the Handcart plug the second, when the switch cabinet doors can not be closed .

     Analysis of more than two ways, we find that there are some hidden dangers: a way to switch into the Handcart to switch the location test, this time by switching equipment and overhaul the state line into line maintenance, switch hands Location of the car to a test, switch contact Handcart cabinet charged by static close contact, and mechanical properties of the switch during the trial, contact switches on all short-wiring folders have a trial, can not be ruled out if the quiet inside touch Closed the first board in the absence of reliable caused by the closure of the discharge. The second way is to use a dedicated connection plugs, switches Handcart do not have to promote the switch inside to avoid the first in a way that may arise insecurity, which is currently in trials widely used. However, this approach makes switch cabinet doors were open, reliable and can not be closed, with security measures in the switch cabinet doors hanging "stop, high-risk" signs do not meet the requirements, and in fact in the cabinet due to static touch First charged, although the board has closed every other living, but in the cabinet can not be reliable because of the closure, resulting in the possibility of collision repair personnel and equipment hidden inside charged.

     2.2 improvements

     Carefully study the structure of high voltage switchboard KYN28A-12, can be seen in the cabinet doors, there is a switch to observe storage instructions and closing hours of observation windows, the current observation window is fixed. Can improve the observation window for the outside activities of the open window, the window switches mounted on the inside of doors, open only when the doors before the event opened from the inside of the window. When the switch repair, maintenance staff and then open the doors to open in the activities of the window, dedicated connection to plug inserted through the window of activity in the second drawer of a plug, and then locked in doors. This will be part of the charged through the doors and maintenance personnel fully separate, so that the improvement will not affect the overall layout of the switchgear and beautiful, but also repair work of the security.

     3 hole on the earth switch operation of the valve problem Electromagnet closed

     3.1 Status and Problems

     KYN28A-12 high voltage switchboard, charged together to prevent the grounding of the switch is grounded by the switching operation to achieve the hole closed the valve. Ground switch operation of the valve hole through the mechanical and electrical chain to achieve open or closed. When the switch is in Handcart running (or hot standby) position, this time by mechanical switches Handcart direct link has been closed grounding switch operation valve hole, making the operation can not be inserted to handle ground operations switch; if Handcart switch in cold standby ( Or maintenance) position, the switch to the Handcart mechanical valve atresia lost, the circuit is not charged at the same time, display live close contact, through electro-magnet circuit, electro-magnet excitation after grounding switch operation could open the valve hole, which can be Switch to operate on the ground.

     KYN28A-12 in the high voltage switchboard operation by the switch to line maintenance (or switch lines and overhaul) operation, a situation often occurs: Handcart switch has to pull cold standby (or maintenance) position and at the same time, after electrical inspection , There is no voltage side of the line, grounding switch operation still can not open the valve hole, which can not co-operate on the earth switches. At this point, only the use of emergency operators to open tools unlock doors under, articulated artificial earth manner to complete the overhaul state line. This makes the process complicated, an increase of operating time.

     Research on the operation took place in such a situation can be found in ground resulted in a switching operation can not open the valve hole, there are three main reasons: First, due to the switch to operate Handcart not in place (before cold stand-by position or location of the maintenance); second valve atresia Damage to the electromagnet; Third, the inherent mechanical valve jam. Deqing Xiangongdianju running in the operation took place can not open the trap door, basically because of damage caused by solenoid valve atresia, and found that repair damage caused by electro-magnet is mainly due to the internal solenoid coil fever burned. When the switch cabinet in line maintenance (or switch lines and overhaul), the live display always-on contact, thus locking solenoid valve connected to power, so that the electro-magnet excitation. Under normal circumstances, the repair work will need to maintain the equipment maintenance line (or line switches and maintenance) for several hours maintenance time to focus even a few days, the solenoid valve closed for several hours or several days in a state of excitation, internal electromagnet Coil heat and electricity for a long time to burn.

     3.2 improvements

     Electromagnet solution damage the fundamental problem, is to electromagnets to minimize the power, without increasing staff to run the operation more difficult. We can within the existing electro-magnet excitation circuit by adding a small button switch and remove the original circuit of AC-DC converter modules (the modules function is to make the electro-magnet excitation is not audible), the solenoid coil is AC-DC dual-coil, can not be replaced

Figure 3 electro-magnet excitation of the circuit to improve

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This small button switch can be installed in the ground next to the hole switch operation, press the small button so that the excitation electromagnet to lift the grounding switch the valve closed, open the trap door on the earth switch operation to insert the handle, then they can open small button at this time can be Ground switch operation, but also cut off power supply electro-magnet, so as to achieve two goals. In addition, when a small button press, the electro-magnet excitation audible, can prompt the operator electromagnet normal circumstances, so as to prevent the operation due to the trap door jam and damage to the miscarriage of justice for the electromagnet.