An automatic power conversion device

Abstract

The present invention discloses an automatic power conversion device. The automatic power conversion device includes at least two actuating switches and a control unit for controlling each actuating switch. Each actuating switch includes a closing control device, a tripping control device, and a position signal feedback unit. The control unit includes a microprocessor, a group of actuating switch control circuits corresponding to the actuating switches one by one, and a position signal detection circuit. The actuating switch control circuit includes a multi-location selection and interlock circuit. The position signal detection circuit is used to transmit the position signal of the position signal feedback unit of the corresponding actuating switch to the microprocessor. The multi-location selection and interlock circuit consists of multiple relays and is used to select one from multiple control mode signals and input it to the actuating switch. The present invention has multi-location (multi-mode) operation and interlock functions, and has a simple circuit structure and strong scalability.

Description

Technical Field

[0001] The present invention relates to an automatic power conversion device, belonging to the technical field of low-voltage power distribution. Background Art

[0002] In modern architecture, communication, chemical industry, finance, medical treatment, fire protection and other fields, higher and higher requirements are put forward for the reliability and continuity of the automatic power supply system in primary and secondary loads. Therefore, multiple power sources are used to ensure continuous power supply to the load through a switching system. The universal circuit breakers at the power supply end are generally installed in different distribution cabinets and are far apart. Taking the conversion of two inlets and one bus tie as an example, generally two high-voltage power sources (such as 10 kV) enter the distribution room, are converted into low voltage (such as 400 V) through transformers, and supply power to the loads carried on the bus after passing through the universal circuit breakers. The transformers are generally placed at both ends of the distribution cabinets in the distribution room, and the corresponding incoming universal circuit breakers are placed in the distribution cabinets at both ends. (1) At present, the universal circuit breakers are centrally controlled by a single controller to ensure the closing / opening operations of each circuit breaker, but the on-site manual control conversion operation cannot be realized. Only the closing / opening can be controlled through the closing / opening buttons of the universal circuit breakers. At the same time, the closing / opening of the universal circuit breakers cannot be manually controlled on the cabinet door, and even less can the closing / opening of the universal circuit breakers be manually controlled in the remote control room. The operation mode is very inflexible and cannot meet the user's demand for multi-location operation. (2) To prevent the two power sources from being connected simultaneously and causing a short circuit, one method is to configure a mechanical interlock to achieve this. However, the existing mechanical interlocks between the actuating switches all have requirements for the installation distance, and the actuating switches of the multi-power switching system are often far apart, and the above mechanical interlock cannot be installed. Another method is to equip an electrical interlock, which is achieved by connecting the auxiliary signals of other switches in series in the closing control circuit. However, especially for a multi-power system, it occupies a large number of auxiliary contacts of the universal circuit breaker and the wiring is quite cumbersome. Therefore, both of the above measures have serious potential safety hazards of short circuit between power sources and may cause unpredictable losses. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an automatic power conversion device with multi-location (multi-mode) operation and interlock functions, and with a simple circuit structure and strong expandability.

[0004] An automatic power conversion device includes at least two actuating switches and a control unit for controlling each actuating switch. Each actuating switch includes a closing control device, a tripping control device, and a position signal feedback unit. The control unit includes a microprocessor, a group of actuating switch control circuits corresponding to the actuating switches one by one, and a position signal detection circuit. The actuating switch control circuit includes a multi-location selection and interlock circuit. The position signal detection circuit is used to transmit the position signal of the position signal feedback unit of the corresponding actuating switch to the microprocessor. The multi-location selection and interlock circuit includes M control interfaces, M - 1 selection relays, and one interlock relay, where M is an integer greater than or equal to 2. Each control interface includes a tripping signal input terminal and a closing signal input terminal. The selection relay has at least two pairs of contact points, and the interlock relay has at least one pair of contact points. When M≥3, the normally open contact input terminals of the first pair of contact points and the second pair of contact points in the i-th selection relay are respectively connected to the closing signal input terminal and the tripping signal input terminal of the (i + 1)-th control interface. The common output terminals of the first pair of contact points and the second pair of contact points in the i-th selection relay are respectively connected to the normally closed contact input terminals of the first pair of contact points and the second pair of contact points in the (i + 1)-th selection relay, where i = 1, 2,..., M - 2. The common output terminal of the first pair of contact points in the (M - 1)-th selection relay is connected to the normally closed contact input terminal in the interlock relay. The common output terminal of the second pair of contact points in the (M - 1)-th selection relay is commonly connected to the control signal input terminal of the interlock relay, the tripping signal input terminal of the first control interface, and the control signal input terminal of the tripping control device of the corresponding actuating switch. The normally closed contact input terminal of the first pair of contact points in the first selection relay is connected to the closing signal input terminal of the first control interface. The common output terminal in the interlock relay is connected to the control signal input terminal of the closing control device of the corresponding actuating switch. When M = 2, the normally open contact input terminals of the first pair of contact points and the second pair of contact points in the selection relay are respectively connected to the closing signal input terminal and the tripping signal input terminal of the second control interface. The common output terminal of the first pair of contact points in the selection relay is connected to the normally closed contact input terminal of the first pair of contact points in the interlock relay. The common output terminal of the second pair of contact points in the selection relay is commonly connected to the control signal input terminal of the interlock relay, the tripping signal input terminal of the first control interface, and the control signal input terminal of the tripping control device of the corresponding actuating switch. The normally closed contact input terminal in the selection relay is connected to the closing signal input terminal of the first control interface. The common output terminal in the interlock relay is connected to the control signal input terminal of the closing control device of the corresponding actuating switch.

[0005] Preferably, the tripping control device is a latching shunt trip.

[0006] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0007] Based on a simple relay group, the present invention constructs a multi-location selection and interlock circuit for each actuator switch in the system, which can realize multi-location or multi-mode operation of the automatic power conversion system, meet various control requirements of users, and both multi-location and multi-mode operations have safe and reliable interlock functions, which can solve the problem that mechanical interlocks cannot be installed over long distances. The technical solution of the present invention has the advantages of flexible setting, simple circuit, and wide application range, and can be expanded according to the actual situation and actual needs, without being limited by the number of actuator switches in the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a structural principle block diagram of the automatic power conversion device of the present invention;

[0009] Figures 2 to 4 It is a schematic diagram of the circuit state of the multi-location selection and interlock circuit in different control modes in the first embodiment of the present invention;

[0010] Figure 5 It is a schematic diagram of the circuit structure of the multi-location selection and interlock circuit in the second embodiment of the present invention;

[0011] Figure 6 It is a schematic diagram of the circuit structure of the multi-location selection and interlock circuit in the third embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] Aiming at the deficiencies of the prior art, the solution idea of the present invention is to construct a multi-location selection and interlock circuit for each actuator switch in the system based on a simple relay group to realize multi-location or multi-mode operation and interlock function of the automatic power conversion system.

[0013] The technical solution proposed by the present invention is specifically as follows:

[0014] An automatic power conversion device includes at least two actuating switches and a control unit for controlling each actuating switch. Each actuating switch includes a closing control device, a tripping control device, and a position signal feedback unit. The control unit includes a microprocessor, a group of actuating switch control circuits corresponding to the actuating switches one by one, and a position signal detection circuit. The actuating switch control circuit includes a multi-location selection and interlock circuit. The position signal detection circuit is used to transmit the position signal of the position signal feedback unit of the corresponding actuating switch to the microprocessor. The multi-location selection and interlock circuit includes M control interfaces, M - 1 selection relays, and one interlock relay, where M is an integer greater than or equal to 2. Each control interface includes a tripping signal input terminal and a closing signal input terminal. The selection relay has at least two pairs of contact points, and the interlock relay has at least one pair of contact points. When M≥3, the normally open contact input terminals of the first pair of contact points and the second pair of contact points in the i-th selection relay are respectively connected to the closing signal input terminal and the tripping signal input terminal of the (i + 1)-th control interface. The common output terminals of the first pair of contact points and the second pair of contact points in the i-th selection relay are respectively connected to the normally closed contact input terminals of the first pair of contact points and the second pair of contact points in the (i + 1)-th selection relay, where i = 1, 2,..., M - 2. The common output terminal of the first pair of contact points in the (M - 1)-th selection relay is connected to the normally closed contact input terminal in the interlock relay. The common output terminal of the second pair of contact points in the (M - 1)-th selection relay is commonly connected to the control signal input terminal of the interlock relay, the tripping signal input terminal of the first control interface, and the control signal input terminal of the tripping control device of the corresponding actuating switch. The normally closed contact input terminal of the first pair of contact points in the first selection relay is connected to the closing signal input terminal of the first control interface. The common output terminal in the interlock relay is connected to the control signal input terminal of the closing control device of the corresponding actuating switch. When M = 2, the normally open contact input terminals of the first pair of contact points and the second pair of contact points in the selection relay are respectively connected to the closing signal input terminal and the tripping signal input terminal of the second control interface. The common output terminal of the first pair of contact points in the selection relay is connected to the normally closed contact input terminal of the first pair of contact points in the interlock relay. The common output terminal of the second pair of contact points in the selection relay is commonly connected to the control signal input terminal of the interlock relay, the tripping signal input terminal of the first control interface, and the control signal input terminal of the tripping control device of the corresponding actuating switch. The normally closed contact input terminal in the selection relay is connected to the closing signal input terminal of the first control interface. The common output terminal in the interlock relay is connected to the control signal input terminal of the closing control device of the corresponding actuating switch.

[0015] Preferably, the tripping control device is a holding type shunt release.

[0016] For the convenience of public understanding, the technical solution of the present invention will be described in detail below through two specific embodiments in conjunction with the accompanying drawings:

[0017] The automatic power conversion device of this embodiment, as Figure 1 shown, includes n execution switches and a control unit for controlling each execution switch. Each execution switch includes a closing control device, a tripping control device, and a position signal feedback unit; as Figure 1 shown, the control unit includes a microprocessor, a group of execution switch control circuits corresponding one-to-one with the execution switches, and a position signal detection circuit. Each execution switch control circuit includes a multi-location selection and interlock circuit. The position signal detection circuit is used to transmit the position signal of the position signal feedback unit of the corresponding execution switch to the microprocessor; the local control signal, the remote control signal, and the automatic control signal (both including the closing control signal and the tripping control signal) output by the automatic control circuit are output to the closing control device and the tripping control device of the corresponding execution switch after passing through the multi-location selection and interlock circuit. The tripping control device in this embodiment is a holding type shunt release.

[0018] The automatic power conversion device can be two power sources, two inlets and one bus tie, three power sources, two inlets, one bus tie and one generator, two inlets, one bus tie and two generators, three inlets and two bus ties, etc. According to the different numbers of execution switches in the system, the corresponding number of circuits is configured. That is, when two power sources are applied, n = 2; when two inlets and one bus tie or three power sources are applied, n = 3; when two inlets, one bus tie and one generator are applied, n = 4; when two inlets, one bus tie and two generators or three inlets and two bus ties are applied, n = 5, and so on.

[0019] The multi-location selection and interlock circuit in this embodiment is as Figures 2 to 4 shown, which are the circuit states in the automatic control mode, local control mode, and remote control mode respectively. It includes 3 control interfaces: an automatic control interface, a local control interface, and a remote control interface, 2 selection relays K1, K2, and an interlock relay K3. Each control interface includes a tripping signal input terminal and a closing signal input terminal. The selection relays K1, K2 have at least two pairs of contacts, and the interlock relay K3 has at least one pair of contacts; as Figures 2 to 4As shown in the figure, the normally open contact input terminals of the first set of contact pairs and the normally open contact input terminals of the second set of contact pairs in the selection relay K1 are respectively connected to the closing signal input terminal and the opening signal input terminal of the local control interface. The common output terminals of the first set of contact pairs and the common output terminals of the second set of contact pairs in the selection relay K1 are respectively connected to the normally closed contact input terminals of the first set of contact pairs and the normally closed contact input terminals of the second set of contact pairs in the selection relay K2. The common output terminal of the first set of contact pairs in the selection relay K2 is connected to the normally closed contact input terminal in the interlock relay K3. The common output terminal of the second set of contact pairs in the selection relay K2 is commonly connected to the control signal input terminal of the interlock relay K3, the opening signal input terminal of the automatic control interface, and the control signal input terminal of the opening control device of the corresponding execution switch. The normally closed contact input terminal of the first set of contact pairs in the selection relay K1 is connected to the closing signal input terminal of the automatic control interface. The common output terminal in the interlock relay K3 is connected to the control signal input terminal of the closing control device of the corresponding execution switch.

[0020] The microprocessor drives the relays K1 and K2 to operate according to the control mode signal selected by the user, and respectively outputs automatic, local, and remote drive signals through contact switching to achieve the multi-location operation function. The control mode setting selected by the user can be set by the controller button, menu setting, or external terminal input setting. The drive source selection logic is shown in Table 1.

[0021] Table 1

[0022] Control method K1 K2 Drive source Automatic control Release Release Controller make / break control signal Local control Make Release Local interface external make / break control signal Remote control — Make Remote interface external make / break control signal

[0023] In the automatic control mode, refer to Figure 2 , the two relays K1 and K2 in the circuit are in the released state. The automatic control signals (closing and opening drive signals) issued by the microprocessor are respectively transmitted to the closing control device and the opening control device of the execution switch through the normally closed contacts in series of these two relays. At this time, the drive signals input by the local control interface and the remote control interface are both invalid. When performing a closing operation, the microprocessor controls the system according to the automatic conversion logic, and judges whether the closing operation can be executed according to the conversion logic. If the conditions for executing the closing operation are not met, the microprocessor issues an opening command. At this time, the interlock relay K3 is energized, the closed point in series in the closing circuit is opened, and the holding shunt is energized to work, and the execution switch cannot be closed. If the closing operation can be executed, the microprocessor cancels the opening command, the interlock relay K3 loses power, the closed point in series in the closing circuit is restored, and the holding shunt loses power and does not work. At this time, the execution switch can be closed, so as to achieve the interlock function.

[0024] In the local control mode, refer to Figure 3, relay K1 is energized and its contacts are switched, disconnecting the closing drive signal sent by the controller, connecting the closing and opening drive signals input from the local control interface, and then delivering them to the closing and opening control device of the actuator switch through the normally closed contacts of relay K2. At this time, both the drive signal input from the remote control interface and the closing drive signal input from the microprocessor are invalid, and the microprocessor still has control authority over the opening signal circuit. When a closing operation is performed, the microprocessor determines whether the closing operation can be executed based on the detected opening and closing status of the system switch. If the conditions for executing the closing operation are not met, the microprocessor issues an opening command. At this time, interlock relay K3 is energized, the normally closed contacts connected in series in the closing circuit are opened, and the holding shunt is energized to operate, and the actuator switch cannot be closed. If the closing operation can be executed, the microprocessor cancels the opening command, interlock relay K3 is de-energized, the normally closed contacts connected in series in the closing circuit are restored, and the holding shunt is de-energized and ineffective. At this time, the actuator switch can receive the closing signal sent from the local control interface to control the actuator switch to close, thus realizing the interlock function;

[0025] In the remote control mode, refer to Figure 4 , relay K2 is energized and its contacts are switched, disconnecting the drive closing signal sent by the controller, connecting the closing and opening drive signals input from the remote control interface, and delivering them to the switch drive circuit. At this time, both the drive signal input from the local control interface and the closing drive signal input from the microprocessor are invalid, and the microprocessor still has control authority over the opening signal circuit. When a closing operation is performed, the microprocessor determines whether the closing operation can be executed based on the detected opening and closing status of the system switch. If the conditions for executing the closing operation are not met, the microprocessor issues an opening command. At this time, interlock relay K3 is energized, the normally closed contacts connected in series in the closing circuit are opened, and the holding shunt is energized to operate, and the actuator switch cannot be closed. If the closing operation can be executed, the microprocessor cancels the opening command, interlock relay K3 is de-energized, the normally closed contacts connected in series in the closing circuit are restored, and the holding shunt is de-energized and ineffective. At this time, the actuator switch can receive the closing signal sent from the remote control interface to control the actuator switch to close, thus realizing the interlock function.

[0026] Figure 5 shows the multi-location selection and interlock circuit of the second embodiment of the present invention, which includes two control interfaces: an automatic control interface, a local control interface (or a remote control interface), one selection relay K1, and one interlock relay K3. Each control interface includes a tripping signal input terminal and a closing signal input terminal. The selection relay K1 has at least two pairs of contacts, and the interlock relay K3 has at least one pair of contacts; as Figure 5As shown, the normally open contact input terminals of the first set of contact pairs and the normally open contact input terminals of the second set of contact pairs in the selection relay K1 are respectively connected to the closing signal input terminal and the opening signal input terminal of the local control interface. The common output terminal of the first set of contact pairs in the selection relay K1 is connected to the normally closed contact input terminal of the interlock relay K3. The common output terminal of the second set of contact pairs in the selection relay K1 is commonly connected to the control signal input terminal of the interlock relay K3, the opening signal input terminal of the automatic control interface, and the control signal input terminal of the opening control device of the corresponding actuating switch. The normally closed contact input terminal of the first set of contact pairs in the selection relay K1 is connected to the closing signal input terminal of the automatic control interface. The common output terminal of the interlock relay K3 is connected to the control signal input terminal of the closing control device of the corresponding actuating switch.

[0027] Figure 6 shows the circuit state of the multi-location selection and interlock circuit of the third embodiment of the present invention in the fourth control mode in addition to the three control modes of automatic, local, and remote control, as Figure 6 shown. It includes 4 control interfaces: an automatic control interface, a local control interface, a remote control interface, and a fourth control interface, 3 selection relays K1, K2, K4, and an interlock relay K3. Each control interface includes a closing signal input terminal and an opening signal input terminal. The selection relays K1, K2, K4 all have at least two sets of contact pairs, and the interlock relay K3 has at least one set of contact pairs; as Figure 6As shown, the normally open contact input terminals of the first set of contact pairs and the normally open contact input terminals of the second set of contact pairs in the selection relay K1 are respectively connected to the closing signal input terminal and the opening signal input terminal of the local control interface. The common output terminals of the first set of contact pairs and the common output terminals of the second set of contact pairs in the selection relay K1 are respectively connected to the normally closed contact input terminals of the first set of contact pairs and the normally closed contact input terminals of the second set of contact pairs in the selection relay K2. The common output terminals of the first set of contact pairs and the common output terminals of the second set of contact pairs in the selection relay K2 are respectively connected to the normally closed contact input terminals of the first set of contact pairs and the normally closed contact input terminals of the second set of contact pairs in the selection relay K4. The common output terminal of the first set of contact pairs in the selection relay K4 is connected to the normally closed contact input terminal in the interlock relay K3. The common output terminal of the second set of contact pairs in the selection relay K4 is commonly connected to the control signal input terminal of the interlock relay K3, the opening signal input terminal of the automatic control interface, and the control signal input terminal of the opening control device of the corresponding actuating switch. The normally closed contact input terminal of the first set of contact pairs in the selection relay K1 is connected to the closing signal input terminal of the automatic control interface. The common output terminal in the interlock relay K3 is connected to the control signal input terminal of the closing control device of the corresponding actuating switch. The mode selection control logic and working principle of the selection relays K1, K2, and K4 are similar to those of the first embodiment. For the sake of brevity, they will not be elaborated here.

Claims

1. An automatic power conversion device, comprising at least two execution switches and a control unit for controlling each execution switch, each execution switch including a closing control device, a tripping control device and a position signal feedback unit; characterized in that, The control unit includes a microprocessor, a group of actuator switch control circuits corresponding one-to-one to the actuator switches, and a position signal detection circuit. The actuator switch control circuit includes a multi-location selection and interlock circuit. The position signal detection circuit is used to transmit the position signal of the corresponding actuator switch's position signal feedback unit to the microprocessor. The multi-location selection and interlock circuit includes M control interfaces, M - 1 selection relays, and one interlock relay, where M is an integer greater than or equal to 2. Each control interface includes a trip signal input terminal and a close signal input terminal. The selection relay has at least two pairs of contacts, and the interlock relay has at least one pair of contacts. When M ≥ 3, the normally open contact input terminals of the first pair of contacts and the second pair of contacts in the i-th selection relay are respectively connected to the close signal input terminal and the trip signal input terminal of the (i + 1)-th control interface. The common output terminals of the first pair of contacts and the second pair of contacts in the i-th selection relay are respectively connected to the normally closed contact input terminals of the first pair of contacts and the second pair of contacts in the (i + 1)-th selection relay, where i = 1, 2, …, M - 2. The common output terminal of the first pair of contacts in the (M - 1)-th selection relay is connected to the normally closed contact input terminal of the interlock relay. The common output terminal of the second pair of contacts in the (M - 1)-th selection relay is commonly connected to the control signal input terminal of the interlock relay, the trip signal input terminal of the first control interface, and the control signal input terminal of the trip control device of the corresponding actuator switch. The normally closed contact input terminal of the first pair of contacts in the first selection relay is connected to the close signal input terminal of the first control interface. The common output terminal of the interlock relay is connected to the control signal input terminal of the close control device of the corresponding actuator switch. When M = 2, the normally open contact input terminals of the first pair of contacts and the second pair of contacts in the selection relay are respectively connected to the close signal input terminal and the trip signal input terminal of the second control interface. The common output terminal of the first pair of contacts in the selection relay is connected to the normally closed contact input terminal of the first pair of contacts in the interlock relay. The common output terminal of the second pair of contacts in the selection relay is commonly connected to the control signal input terminal of the interlock relay, the trip signal input terminal of the first control interface, and the control signal input terminal of the trip control device of the corresponding actuator switch. The normally closed contact input terminal of the selection relay is connected to the close signal input terminal of the first control interface. The common output terminal of the interlock relay is connected to the control signal input terminal of the close control device of the corresponding actuator switch.

2. The automatic power conversion device according to claim 1, wherein The trip control device is a latching shunt trip.

Images