A controller for electric power distribution apparatus

Abstract: Object of the present invention is to provide a controller for distribution apparatus which prevents extension of power failure. When a short circuit accident, for example, occurs in one control circuit (100A) for distribution apparatus, a breaker (15) for distribution opens, an auxiliary coil (18A) becomes unexcited, and power failure is caused, but an auxiliary contact point (18B) of the unexcited auxiliary coil (18A) closes in another control circuit (100B) for distribution apparatus so as to excite a closing coil (10), and consequently, the other control circuit (100B) starts its operation immediately. Accordingly, extension of the power failure can be prevented and reliability of power supply can be safely maintained.

Description: The present invention relates to a controller for electric power distribution apparatus in which an interlock condition among lined apparatus is improved. Generally, electric power is supplied to loads from electric power companies. But, when a power failure is caused by an accident, such loads which are necessitated to prepare for a long time power outage as hospitals, computer power sources etc. switch over a power source from the electric power company to private power generation. A controller for electric power distribution apparatus having interlock conditions is used for the switching over the power source from electric power company to the private power generation. The interlock condition is so settled that power supply from the private power generation is absolutely prohibited when power is being supplied from the electric power company. Reversely, power supply from the electric power company is absolutely prohibited when power is being supplied from the private power generation. The controller used in the above described case is such an apparatus having control lines among a plurality of distribution apparatus and control distributing lines which are connected in parallel between the control lines of positive side and the control lines of negative side.The control distributing lines are arranged to each distribution apparatus. The control lines connect such interlock switches as operation switches and closing coils having the interlock conditions. The interlock switch connects, for example, the B contact point which operates the closing coil at the electric power company side to, for example, the control distributing line at the private power generation side, and also connects the B contact point for the closing coil at the private power generation side to the control distributing line at the electric power company side. Accordingly, when the closing coil at the electric power company side is excited, the B contact point of the closing coil at the private power generation side remains open, and electric current does not flow to the control distributing line. Such control circuit as above described is disclosed in, for example, JP-A-63-178737 (1988). In accordance with the above described prior art, there is a disadvantage that power failure-is caused when an accident is generated in the control distributing line at the electric power company side, because electric current does not flow to all of control distributing lines at both the electric power company side and the private power generation side. The above described disadvantage can also occur on all of closed type distributing apparatus. There is another disadvantage that all of the distribution apparatus cause power failure when some of the distribution apparatus are additionally installed because the control distributing lines are mutually wired in a plurality of distribution apparatus. GB-A-793 369 discloses a controller for electric power distribution apparatus, comprising at least two main circuit breakers for distribution, a closing coil for closing each main circuit breaker and at least one contact for controlling the current flowing through said closing coil and being actuated by a separate circuit breaker. One of the objects of the present invention is to provide a. controller for electric power distribution apparatus which maintains a reliability for power supply by preventing spread abroad of power failure. Other object of the present invention is to provide a controller for electric power distribution apparatus which is prevented from power failure when additional apparatus are installed. The objects are met by the invention as set out in claim 1. In accordance with the controller for electric power distribution apparatus relating to the present invention, when a short-circuit accident, for example, is generated in the control circuit for distribution apparatus, the breaker for distribution is opened, the auxiliary coil becomes not-excited state, and power failure is caused, but, the auxiliary contact point of the not-excited state auxiliary coil in other control circuit for distribution apparatus closes and the closing coil is excited, and accordingly, the other control circuit for distribution apparatus is operated and power failure can be prevented. Further, the auxiliary coil in other control circuit for distribution apparatus is excited and the auxiliary contact point in the other control circuit for distribution apparatus is kept open, and accordingly, even though an operator operates the closing coil in the control circuit for distribution apparatus by a mistake, the closing is impossible and safety can be maintained. Brief Description of the Drawings FIG. 1 is a front view of a controller for distribution apparatus illustrating an embodiment of the present invention, and FIG. 2 is a wiring diagram indicating wiring of the control circuit for the distribution apparatus in FIG. 1. Hereinafter, embodiments of the present invention are explained referring to FIGs. 1 and 2, which respectively illustrate a front view and a control circuit diagram of the controller for electric power distribution apparatus. A plurality of distribution apparatus 1A, 1B, ... 1N and the integrated controller 2 are arranged in a lined apparatus. As each of the distribution apparatus has the same structure, the explanation is performed taking the first and the second distribution apparatus 1A, 1B for examples. The first and the second distribution apparatus 1A, 1B respectively have the disconnecting portion 3 inside. The first and the second breakers 4, 5 electrically close or open the disconnecting portion 3. The first and the second distribution apparatus 1A, 1B, and the first and second breakers 4, 5, are provided with the closing control line 6 and the auxiliary control line 7 for a control circuit. The closing control line 6 of the distribution apparatus 1A, 1B, connects the operation switch 8, and the closing coils 9, 10. By operating the operation switch 8 to excite the closing coils 9, 10, each of breakers 4, 5, is connected or disconnected. The closing contact points 9A, 10A, which are closed by excitation of the closing coils 9, 10, are connected to the auxiliary control line 7. And, the disconnecting portion is provided to both the control lines 6, 7. Terminals of the closing control line 6 and the auxiliary control line 7 at the distribution apparatus side are connected to a plurality of the connectors 12 in the integrated controller 2 through the tie cables 13 which are connected to each of the connectors 11 at the distribution apparatus side. A plurality of the tie cables 13 are arranged in the underground cable pit 14 which is formed under floors of each distribution apparatus 1A, 1B, ... 1N and the integrated controller 2. The direct current control bus bar 17 and the control lines 6, 7, are connected to the primary side and secondary side of the first and the second breakers 15, 16, for distribution in the integrated controller. The auxiliary coils 18A, 19A and the auxiliary contacting points 18B, 19B are connected to the auxiliary control line 7 and the closing control line 6 between the breakers 15, 16, for distribution and the connector 12. The auxiliary coils 18A, 19A are excited by closing of the closing contact points 9A, 10A. The auxiliary contact points 18B, 19B become open by excitation of the auxiliary coils 18A, 19A, that means performing a reverse operation. The distribution apparatus 1A, 1B having the closing control line 6 and the auxiliary control line 7 from the breakers 15, 16 for distribution to the closing coils 9, 10 and corresponding parts of the integrated controller 2 are generically called the first and the second (regular and standby) control circuits for distribution apparatus 100A, 100B. Each of the control circuit for the distribution apparatus 100A, 100B, is connected to the primary side direct current control bus bar 17 of the first and the second breakers 15, 16, for distribution, and is electrically independent of each other. The auxiliary contact point 18B which becomes open by exciting of the auxiliary coil 18A of the one control circuit for the distribution apparatus 100A is connected to the closing control line 6 of the other control circuit for the distribution apparatus 100B. Further, the auxiliary contact point 19B which openes by exciting of the auxiliary coil 19A of the other control circuit for the distribution apparatus 100B is connected to the closing control line 6 of the first control circuit for the distribution apparatus 100A. In the present embodiment, two of the control circuits for distribution apparatus 100 are installed, but more than two control circuits are also usable. And, as for the integrated control apparatus, a plurality of independent control apparatus or control portions are usable. Next, referring to FIG. 2 illustrating control circuits, operation of the first and the second control circuits for distribution apparatus 100A, 100B is explained. In a case of the first breaker 4 closing, the first closing coil 9 is excited by closing the operation switch 8, and the first closing contact point 9A is closed and the first auxiliary coil 18A is excited, while, the first auxiliary contact point 18B, which is installed at the side of the second control circuit for the distribution apparatus 100B, and operates reversely to the first auxiliary coil 18A and remains open. But, the second auxiliary contact point 19B remains closed because the second auxiliary coil 19A is not excited. Accordingly, the first breaker 4 is in a closed condition and the second breaker 5 is in an open condition. Owing to the above described condition, actuating the operation switch 8 of the control circuit side of the second distribution apparatus 100B has no effect even if the operator erroneously operates it, and an interlock condition is established. In accordance with the present invention, safety of operation is guaranteed as above described by such a simple structure that only the first auxiliary contact point 18B and the second auxiliary contact point 19B are interchanged. When a short circuit accident occurs at the portion marked "X 20" in the auxiliary control line 7 of the first distribution apparatus 1A under the above described condition and the breaker for the first distributing apparatus 15 opens, the first closing coil 9 takes an unexcited condition, the first breaker 4 opens, and the control circuit side for the first distribution apparatus 100A causes power failure. At that time, the first auxiliary coil 18A takes an unexcited condition, the first auxiliary contact point 18B is closed, the second closing coil 10 is excited, so that the control circuit for the second distribution apparatus 100B is operable, and accordingly, extension of the power failure caused by the accident can be prevented. The above described feature of the present invention has an advantage that additional installation of the first breaker 4 can be performed with simultaneous operation of the second breaker 5 when the first breaker 4 is additionally installed at an adjacent place to the second breaker 5. Besides, an arrangement of the tie cable 13 which connects each distribution apparatus 1A, ... 1N, and the integrated controller 2 through the connectors 11, 12, at the underground cable pit 14 causes such an advantage that extension of fire can be prevented when a fire occurs, for example, in the first distribution apparatus 1A. Although each distribution apparatus is separated from the adjacent distribution apparatus with steel plates and fire extension is scarcely anticipated, there is a possibility that the fire extends to the adjacent distribution apparatus and the integrated controller through the tie cable 13. But, the fire extension can be prevented by arrangement of the tie cable 13 in the underground cable pit 14 because the tie cable 13 is thus less burnable. Further, hitherto a great deal of working time and workers have been required for a performance testing between each distribution apparatus 1A, ... 1N, and the integrated controller 2 when the tie cable 13 were not used, because the performance testing was carried out once in the factory using temporal wiring between the each distribution apparatus and the integrated controller, and, after the apparatus were installed at each designated location in a predetermined place, for example, a transforming station of a building, the performance testing was again carried out by the installing workers using temporal wiring between the distribution apparatus and the integrated controller. But, in accordance with the present invention, working time and workers necessary for the wiring can be remarkably reduced, because connection between the each distribution apparatus 1A, ... 1N, and the integrated control apparatus 2 has been facilitated by using the tie cable 13 through the connectors 11, 12. Further, in accordance with an embodiment of the present invention, a display lamp S in the front panel is lit on so as to prevent an erroneous operation of workers when the closing contact points 9A, 10A and the auxiliary contact points 18B, 19B, are closed. As for the embodiment of the present invention, the above described effect can be realized by providing control circuits for distribution apparatus having the first auxiliary coil to a plurality of distribution apparatus themselves and providing the first auxiliary contact point 18B which closes when the first auxiliary coil is in an unexcited condition to the adjacent distribution apparatus. Further, the control circuit for distributing apparatus can be provided to the electric company side supply system and private generation system of the net work receiving facility.

Claims: A controller for electric power distribution apparatus, comprising an integrated controller (2) and first and second control circuits (100A, 100B) for corresponding first and second power distribution apparatus (1A, 1B) each having a main circuit breaker (4, 5) with at least one contact (9A, 10A) and a closing coil (9, 10) for closing said contact (9A, 10A), characterised in that closing control lines (6) and auxiliary control lines (7) connect each of the first and second control circuits (100A, 100B) with the integrated controller (2), that the integrated controller (2) has auxiliary circuit breakers (15, 16) by which each said control circuit (100A, 100B) is connected to a control bus bar (17), that the integrated controller (2) has further auxiliary coils (18A, 19A) and auxiliary contacts (18B, 19B) for controlling the current flowing through said closing coils (9, 10), that each said contact (9A, 10A) of said control circuits (100A, 100B) is connected via one of said auxiliary control lines (7) to one of the auxiliary coils (18A, 19A) for energising said auxiliary coil (18A, 19A) upon energisation of said corresponding closing coil (9, 10), and that each auxiliary coil (18A, 19A) corresponding to one of said control circuits (100A, 100B) actuates the auxiliary contact (19B, 18B) connected to the closing coil (9, 10) of the other of said control circuits (100B, 100A) via one of said closing control lines (6), wherein said contact is in its closed state when its corresponding actuating auxiliary coil (18A, 19A) is deenergised. The controller of claim 1, wherein a connector (11) at the controller side and a connector (12) at the distribution apparatus side are interconnected by a tie cable (13), whereby electrical contact is established between the closing control line (6) and the auxiliary control line (7) on the one hand and between the auxiliary coil (18A, 19A), the auxiliary contact (18B, 19B) connected to the closing coil (9, 10) and the auxiliary circuit breaker (15, 16) on the other hand. The controller of claim 2, wherein said tie cable (13) is arranged in a cable pit (14) provided under the distribution apparatus (1A, 1B) and the controller (2).

Inventors: TANIMIZU TORU, TANIMIZU, TORU
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1992
Main classification: H02J9
IPC codes: H02B3, H02B1, H02J9