It is always difficult to avoid the blackout of the Luye Zhidian system in Jiangmen City, Guangdong Province. In order to reduce the power-off time, for some important production sites, such as continuous operation of the automated production line, it is necessary to use two separate power sources for power supply, and each other is spare, and has a self-injection function. In this way, once a loop has a power outage, the other loop can be quickly put in, thus speeding up the production recovery process of the process equipment.
If the circuit breaker DW1 also sends a closing signal to the DW3, the DW3 is combined, and the power of the segment line is immediately transmitted to the I segment line via the circuit breaker DW3. However, since the dl short-circuit fault point on the I-segment line has not been eliminated, the short-circuit current flows through the DW3 into the circuit breaker DW2, and the circuit breaker DW2 may be short-circuit protected before the DW3. This will cause the I and n lines to be powered off. That is to say, the short circuit of the I section of the two-way mutual power supply system is short-circuited and the power failure is extended to the n-segment line. In the factory power supply system, in order to improve the reliability of the power supply, it is generally possible to use two circuits for power supply. The main circuit of the two-way power supply system can be wired as shown. DW1 and DW2 are two independent power supply line connections. DW1 and DW2 are the main distribution breakers of two independent power supply lines, and DW3 is two independent. Contact breaker between power supplies. The technical performance of the circuit breakers DW1 and DW2 should be considered to meet the requirements of the separate power supply to the load in the own area (ie, the requirements of overload and short circuit protection) when the DW3 contact breaker is disconnected, and to meet the requirements of a certain power supply. When the contact breaker DW3 is closed, one power supply provides overload and short circuit protection for the simultaneous supply of the two sections of the line. For the circuit breaker DW3, the current may flow from the T1 or T2 transformer when it is closed, so the circuit breaker DW3 must be used for both the upper and lower incoming lines, and the performance is the same as DW1 and DW2. Therefore, the DW3 can use the ME series circuit breaker as the tie breaker. Under normal conditions, the power of the I-segment line is supplied by the transformer T1 via DW1, and the power of the segment line is supplied by the transformer T2 via DW2, and the DW3 circuit breaker is connected between them.
When transformer T1 fails power failure or the power supply line loses voltage, the circuit breaker DW1 is disconnected, and the I section line is powered off, so the contact breaker DW3 is closed. At this time, the equipment on the I section line is powered by the transformer T2 via DW2. DW3 is supplied, so the I-segment line is quickly restored. Similarly, when the transformer T2 fails or the power supply line loses voltage, the circuit breaker DW2 is disconnected, and the n-segment line is powered off, so the contact breaker DW3 is closed. During this period, the equipment on the line is powered by the transformer T1 via DW1. DW3 is supplied, so the segment line is also quickly restored.
It can be seen that if a power distribution circuit breaker is tripped, the contact breaker DW3 will blindly and automatically vote, which is obviously not acceptable. Therefore, when a certain line is short-circuited in the two-way power supply system, the DW3 cannot be closed after the corresponding distribution breaker is tripped. That is, when a power failure occurs in the I or n lines, different signals should be transmitted to the circuit breaker DW3, and the different signals are used to control whether the contact breaker DW3 is turned on or not.
In order to enable the contact breaker of the power supply system to automatically and safely invest, the closing operation of the contact breaker DW3 can adopt the circuit as shown (in which the button control circuit for opening and storing energy is not shown), DW3 is the electric closing control device for the contact breaker. DF1 and DF2 are auxiliary contacts of DW1 and DW2, respectively. The circuit breaker is closed and the auxiliary contact is opened; the circuit breaker is opened and the auxiliary contact is closed. SI and S2 are the short-circuit release latching signal contacts of DW1 and DW2, respectively. The function of the intermediate relay 1K is to ensure that the control circuit has a power supply when a power failure occurs in any of the lines. Thus, when DW1 and DW2 are tripped, there are two different contacts of DF1, DF2 and Sl, S2 to control whether the contact breaker DW3 is closed. Next, we analyze the circuit.
When the system is powered normally (before the two power supplies are separately powered, the transfer switch 1SA is placed in the “0†position, the 1SA is placed in the “1†position after the power supply), and the distribution breakers DW1 and DW2 are respectively closed. Transformer T1 supplies power to the I-segment line through DW1, and transformer T2 supplies power to the D-segment line through DW2. Since DF1 and DF2 are separated because DW1 and DW2 are closed, DW3 is not closed, and the two power supply systems are not connected at this time. Automatic input of the contact breaker Under normal circumstances, the two power supplies are independently powered. However, when a power failure occurs in a certain circuit in a power supply system, it takes a long time to manually connect the contact breaker DW3. Therefore, in order to minimize the power-off time of the electrical equipment, it is necessary to make the contact breaker automatically input.
In order to achieve automatic injection of the tie breaker, when a distribution breaker is disconnected, the signal must be passed to the tie breaker to close it. And the contact breaker should accept and execute the signals sent by the two distribution breakers.
When the transformer T1 fails and the power is cut off or the power supply line loses pressure, the circuit breaker DW1 trips due to the undervoltage release action, and at the same time, the DW3 is closed, and the power of the segment line is supplied to the I segment line through the DW3. If the dl point short-circuit fault occurs in the I-segment line, the short-circuit current 4 generated flows through the DW1 circuit breaker, and DW1 trips due to the action of the short-circuit protection trip unit. At this time (the non-important defect in the k-gas era is temporarily suspended, waiting When the power grid is transformed, it will be handled together.
Substation switch (or segmentation switch), so that the line borrows electricity without power failure.
3) The Production Section sends the power outage plan to the dispatching room. The dispatching room determines the operating plan of the power grid according to the power-off operation of the power outage, and passes the line without the power outage request through the tie switch. With the continuous improvement of the distribution network management and operation level, the expansion is completed. The new user is wired and continues to transmit power to reduce the power outage range.
4) The dispatching room reports the power outage plan to the production director for approval.
5) Discharge the power outage plan to the public through television, radio, newspapers, and paging stations, and give it to all production departments and teams. Each team will adjust the production plan according to the power outage plan. In the next week, in addition to accidents, it is generally no longer necessary to arrange power outages caused by power outages. It has become a major obstacle to further improve the reliability of distribution network power supply. It is imperative to carry out distribution network live operation. Due to the charging operation, there are certain requirements for the installation of the line: for example, the three-phase conductors should be horizontally arranged, and the distance between the lines should be large. Therefore, in the future construction and renovation of distribution networks, full consideration should be given to the requirements for live lines for live working, and the successful experience of multiple exchanges and absorption of live working.
The vacuum load switch used on the large branch uses a new generation vacuum load switch with fuse protection. For the large branch of the FWZ-12/630 vacuum load switch installed, when the branch has power failure, it is arranged to install the RW7-10 drop fuse for protection on one pole.
Application of Information System Since September 1998, the Bureau has cooperated with Gaozhi Company to develop MIS information management system (including GIS Geographic Information System). MIS uses Developi2000 as a development tool and applies ORACLE database; GIS uses ORACLE as the information base, and Mapinfo and MAPX as the running platform. MIS reflects the data in ORACLE in the form of a traditional relational database, and GIS converts the abstract electricity consumers, towers, distribution lines, transformers, switches, and substations in ORACLE traditional data into electronic maps. The location, visual effects, and point, line, and surface of the attribute data use the same back-end database. The data in the MIS can be completely called on the GIS platform, and the data completed in the GIS is also reflected in the MIS. In October 1999, the Bureau opened the optical cable in the whole area, and the MIS (and GIS) system was also fully commissioned. The MIS system function module of our office is as shown.
At present, the formulation of the weekly (blackout) plan of our bureau is completed on MIS.
In addition, the fault location function in the distribution network GIS geographic information system brings us great convenience in dealing with faults: when the power user fails or powers down, as long as the user name is reported, the user can be assigned on the GIS. Change the name, and the position of the distribution on the map; and list the knife gates and circuit breakers that control the line where the distribution is located, in order to quickly find the fault point and create conditions for timely isolation of the fault. At the same time, click on the faulty tower on the GIS to list the types and technical parameters of various power equipment on the pole. The maintenance personnel can prepare the materials for fault repair according to the equipment material list provided on the GIS, and further improve the speed of fault handling.
Our bureau has realized the thermal downfall of the distribution line in the urban area, that is, when the line requires contact, first close the contact switch to make the two lkV lines run in a loop, and then disconnect the function module of the Zhenhai Bureau MIS system (Continued from page 31) When a power supply line loses voltage or power failure (such as the I section line), the circuit breaker DW1 trips due to the undervoltage release action, and its auxiliary contact DF1 is closed, so that DW3 is closed, so the power supply is replaced by the transformer T2. It is transmitted to the I segment line via DW2 and DW3. Therefore, the power outage line quickly receives power supply.
When a short circuit occurs in a power supply line (for example, a short circuit occurs at the dl point of the I-segment line), the short-circuit current generated flows into the circuit breaker DW1, and the circuit breaker DW1 trips due to the action of the short-circuit release, and the lock device is broken. The DW1 lock is in the short-circuit trip state, and the signal blocking contact S1 is separated, so that the middle DW3 does not close. Therefore, the short circuit fault of one power supply line does not affect the other power supply line. In this way, the safety and reliability of the automatic connection of the contact breaker is guaranteed.
When the single-loop power supply encounters a power outage, the power equipment completely stops, and the two-way power supply system compensates for the shortage of the single-loop power supply, thereby greatly improving the reliability of the power supply. At the same time, the contact breaker design has the function of automatic investment, which can greatly reduce the power-off time of the electrical equipment, which is conducive to the smooth progress of various production activities. (Received 200102 d gas era
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