CN220933939U - Electrical interlock device for a transfer switch system and transfer switch system - Google Patents

Abstract

Embodiments of the present disclosure provide an electrical interlock for a transfer switch system and a transfer switch system. The electrical interlock device includes: a pair of relays, each relay of the pair of relays comprising: a main contact coupled to a closing control port of a corresponding circuit breaker of the pair of circuit breakers; a coil arranged to close the main contact after being energized; and an auxiliary contact arranged in series with the coil of the other relay to form a part of a coil power supply loop and being in anti-phase with the on-off state of the main contact of the relay; and a control power module. Thus, an interlock can be achieved between the circuit breakers of the two power sources, and in addition, the auxiliary contacts of the relay are coupled to the status indication contacts of the corresponding circuit breakers, the on-off state of the status indication contacts being in anti-phase with the on-off state of the circuit breaker in which it is located. Thereby, a second interlock is realized between the circuit breakers of the two power sources, and the electrical safety performance is improved.

Description

Electrical interlock device for a transfer switch system and transfer switch system

Technical Field

Example embodiments of the present disclosure relate generally to the field of electrical equipment, and in particular, to an electrical interlock for a transfer switch system and a transfer switch system.

Background

In an automatic transfer switch system, there are a common power source and a standby power source, where the common power source and the standby power source have different sources, so as to ensure that when the common power source is not available, the automatic transfer switch system timely switches power supply to the standby power source. In general, the common power source can be from commercial power, and the standby power source can be from commercial power or a generator in different ways.

In a transfer switch system, electrical isolation between a common power supply and a standby power supply needs to be ensured, and an interlocking device is usually required to be additionally arranged between the two power supplies, so that short circuit faults between the two power supplies are avoided. The conventional interlock device directly operates the circuit breakers through an electric actuator such as a motor, and mechanically performs the interlock between the two circuit breakers. However, the interlocking device has the defects of complex structure and high failure rate.

Disclosure of utility model

In a first aspect of the present disclosure, an electrical interlock for a transfer switch system is provided. The transfer switch system comprises a pair of circuit breakers for respectively controlling the on-off of the common power supply loop and the standby power supply loop. The electrical interlock device includes: a pair of relays, each relay of the pair of relays comprising: a main contact coupled to a closing control port of a corresponding circuit breaker of a pair of circuit breakers and adapted to allow the circuit breaker to close a power circuit in which it is located after closing; a coil arranged to close the main contact after being energized; and an auxiliary contact arranged in series with the coil of the other relay of the pair of relays to form a part of a coil power supply loop and being in anti-phase with the on-off state of the main contact of the relay; and a control power module coupled to the coil power supply loop and adapted to allow power to be supplied to coils in the coil power supply loop if the auxiliary contacts are closed.

In some embodiments, the auxiliary contact of each relay is coupled to a status indication contact of the corresponding circuit breaker, the on-off state of the status indication contact being in anti-phase with the on-off state of the circuit breaker in which it is located.

In some embodiments, controlling the power module includes: and the input end of the control power supply circuit is coupled to the common control power supply and the standby control power supply, and the output end of the control power supply circuit is coupled to the state indication contacts of the pair of circuit breakers.

In some embodiments, controlling the power module includes: and a power supply selection unit coupled between the control power supply circuit and the main contact of the relay and adapted to supply power to at least the closing control coil of the circuit breaker via the closing control port.

In some embodiments, the electrical interlock device further comprises: a micro control unit comprising: a pair of output ports adapted to output a high level signal or a low level signal; and the base electrodes of the pair of triodes are respectively coupled to the output ports of the micro-control unit, the collector electrodes of the pair of triodes are respectively coupled to the coil power supply loop, and the emitter electrodes of the pair of triodes are grounded.

In some embodiments, the micro control unit further comprises: and the power supply detection port is coupled to the control power supply circuit and is suitable for receiving a power supply working signal of the control power supply circuit.

In some embodiments, the micro control unit further comprises: and a control signal output port coupled to the power supply selection unit and adapted to output a control signal to the power supply selection unit according to the power supply operation signal so that a corresponding one of the normal control power supply and the standby control power supply supplies power to the relay.

By connecting the coil of the relay in series to the auxiliary contact of the other relay, the main contacts of the two relays are thus associated with each other, and after the main contact of one relay is closed, the main contact of the other relay cannot be closed. Thus, the interlocking between the two relays is realized, and the first heavy electric interlocking between the two circuit breakers is further realized. Further, the state indicating contact of the circuit breaker is coupled to the coil power supply loop, so that the state of the circuit breaker can directly control the on and off of the coil power supply loop, the second electric interlocking is realized, and the working stability and reliability of the electric interlocking device are further improved.

In a second aspect of the present disclosure, a transfer switch system is provided. The transfer switch system includes: a pair of circuit breakers, each coupled to two independent power sources, and each comprising: a closing control port adapted to control at least the conduction of the circuit breaker, and a state indication contact arranged with the on-off state inverted to the on-off state of the circuit breaker in which it is located; and an electrical interlock device according to the first aspect of the present disclosure, coupled between a pair of circuit breakers.

It should be understood that what is described in this section of the disclosure is not intended to limit key features or essential features of the embodiments of the disclosure, nor is it intended to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, wherein like or similar reference numerals denote like or similar elements, in which:

FIG. 1 shows a circuit schematic of a transfer switch system of an embodiment of the present disclosure; and

Fig. 2 shows a simplified circuit schematic of a relay according to an embodiment of the present disclosure.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure have been illustrated in the accompanying drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will be more thorough and complete. It should be understood that the drawings and embodiments of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

It should be noted that any section/subsection headings provided herein are not limiting. Various embodiments are described throughout this document, and any type of embodiment may be included under any section/subsection. Furthermore, the embodiments described in any section/subsection may be combined in any manner with any other embodiment described in the same section/subsection and/or in a different section/subsection.

In describing embodiments of the present disclosure, the term "comprising" and its like should be taken to be open-ended, i.e., including, but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions are also possible below. The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below.

As mentioned briefly above, when a powered device switches between a utility power source and a backup power source, it is desirable to ensure electrical isolation between the utility power source and the backup power source. Typically by interlocking means of a change-over switch system. Specifically, the transfer switch system comprises two circuit breakers, the two circuit breakers are respectively coupled to a common power supply and a standby power supply, an interlocking device is arranged between the two circuit breakers, the traditional interlocking device is interlocked through a mechanical structure, for example, a mechanical connecting rod is coupled between the two circuit breakers, and when one circuit breaker is closed, the mechanical connecting rod drives the other circuit breaker to break, so that the interlocking between the two circuit breakers is realized.

However, these mechanical interlocks are complex in construction and require two circuit breakers in adjacent positions. On the other hand, the mechanism is easy to wear due to the positive pressure between the interlocking mechanisms, so that the mechanism is damaged; and it is inconvenient to release the interlock after the mechanical structure fails.

An electrical interlock for a transfer switch system and a transfer switch system according to embodiments of the present disclosure solve or at least partially solve the above-described and other potential problems with conventional solutions. According to various embodiments of the present disclosure, a portion of a coil power supply loop is formed by arranging two relays with auxiliary contacts between a pair of circuit breakers of a transfer switch system (the auxiliary contacts are arranged in opposition to the main contact on-off state of the relay), and coupling the auxiliary contacts of each relay to a state indicating contact of the circuit breaker (the auxiliary contacts of the circuit breaker are in opposition to the on-off state of the circuit breaker) after the auxiliary contacts of the other relay are connected in series with the coil of the other relay. So that when the utility power source is not available, a circuit breaker coupled to the utility power source opens, while the state of the circuit breaker indicates that the contact is closed. The state indicates that the coil power supply loop where the contact is conductive. The coil works and attracts the main contact of the relay to conduct the switching-on circuit of the breaker coupled to the standby power supply, so that the breaker coupled to the standby power supply is controlled to be closed, and the switching from the common power supply to the standby power supply is completed.

That is, in an embodiment of the present disclosure, in a first aspect, by connecting a coil of a relay in series to an auxiliary contact of another relay, thereby the main contacts of two relays are associated with each other, and after the main contact of one relay is closed, the main contact of the other relay cannot be closed. Thus, the interlocking between the two relays is realized, and the first heavy electric interlocking between the two circuit breakers is further realized.

In the second aspect, the state indicating contact of the circuit breaker is coupled to the coil power supply loop, so that the state of the circuit breaker can directly control the on and off of the coil power supply loop, thereby realizing second electric interlocking and further improving the working stability of the electric interlocking device.

Fig. 1 shows a simplified circuit schematic of a transfer switch system of an embodiment of the present disclosure. As shown in fig. 1, a transfer switch system according to an embodiment of the present disclosure generally includes a pair of circuit breakers 1 (hereinafter also referred to as a first circuit breaker 1a and a second circuit breaker 1 b) coupled to a common power supply circuit (including, for example, a common power supply 4 and a connected load) and a backup power supply circuit (including, for example, a backup power supply 5 and a connected load), respectively, and an electrical interlock device disposed between the pair of circuit breakers 1. The first circuit breaker 1a and the second circuit breaker 1b control on-off of the power supply circuit and the standby power supply circuit, respectively, as needed. For example, the first circuit breaker 1a is coupled between the mains supply and the load to close when the mains supply 4 is available to power the load using the mains supply. The second circuit breaker 1b is coupled between the backup power source 5 and the load to close to power the load using the backup power source 5 when the utility power source 4 is not available. In some embodiments, the common power source 4 may be from mains and the backup power source 5 may be from a generator.

The electrical interlock device includes a pair of relays 2 (hereinafter also referred to as a first relay 2a and a second relay 2 b) and a control power supply module 3. In some embodiments, the electrical interlock device further comprises a micro-control unit, as will be further described below.

The circuit breaker 1 comprises a closing control port 11 and a status indicating contact 12. The switching-on control port 11 is coupled with a switching-on circuit, one end of the switching-on circuit is coupled to a control power supply, and the other end of the switching-on circuit is grounded. When current passes through the switching-on circuit, the switching-on control port 11 can drive the breaker 1 to be closed. The status indicating contact 12 is configured such that its on-off state is opposite to the on-off state of the circuit breaker 1, for example, when the circuit breaker 1 is in the on-state, the status indicating contact 12 is in the off-state, and when the circuit breaker 1 is off, the status indicating contact 12 is switched to be on.

Fig. 2 shows a simplified circuit schematic of a relay according to the present disclosure. As shown in fig. 1 and 2, the relay 2 includes a coil 23, a main contact 21, and an auxiliary contact 22. The coil 23 is adapted to attract the main contact 21 after energizing, so that the main contact 21 is closed. When the coil 23 is not in operation, the main contact 21 is kept in an open state under the drive of a spring mechanism in the relay 2. The auxiliary contact 22 is arranged in opposition to the on-off state of the main contact 21, for example, when the main contact 21 is in the on-state, the auxiliary contact 22 is in the off-state, and when the main contact 21 is switched to the off-state, the auxiliary contact 22 is switched to the on-state. In some embodiments, the connection between the main contact 21 and the auxiliary contact 22 of the relay 2 can be achieved by a coupled mechanical link between the main contact 21 and the auxiliary contact 22.

The pair of circuit breakers 1 and the pair of relays 2 are in one-to-one correspondence, and main contacts 21 of the relays 2 corresponding to the circuit breakers 1 are coupled in a closing circuit of the circuit breakers 1, so that the opening and closing of the closing circuit are controlled. For example, the main contact 21 of the first relay 2a is coupled in the closing circuit of the first circuit breaker 1a, and when the main contact 21 of the first relay 2a is in the closing state, the closing circuit of the first circuit breaker 1a is turned on, so that the first circuit breaker 1a is closed (i.e., turned on). Similarly, the main contact 21 of the second relay 2b is coupled in the closing circuit of the second circuit breaker 1b, and when the main contact 21 of the second relay 2b is in the closing state, the closing circuit of the second circuit breaker 1b is turned on, so that the second circuit breaker 1b is closed (i.e., turned on).

In some embodiments, the main contact 21 of the relay 2 is coupled to the incoming line end and the outgoing line end of the switching-on circuit at the same time, so as to control the on-off of the incoming line and the outgoing line of the switching-on circuit at the same time, thereby improving the electrical safety distance and improving the reliability of the electrical interlocking device.

As shown in fig. 1 and 2, the auxiliary contact 22 of each relay 2 is connected in series with the coil 23 of the other relay 2, and the auxiliary contact 22 is coupled to the status indication contact 12 of the circuit breaker 1 as a part of the coil power supply loop of the coil 23 after being connected in series with the coil 23. Specifically, one end of the auxiliary contact 22 of the first relay 2a is coupled with the coil 23 of the second relay 2b, so that when the auxiliary contact 22 of the first relay 2a is closed (when the main contact 21 of the first relay 2a is in an open state) and there is a potential difference across the coil power supply circuit in which the auxiliary contact 22 of the first relay 2a is located, a current passes through the coil 23 of the second relay 2b, so that the coil 23 of the second relay 2b can attract the main contact 21 of the second relay 2b to be closed.

Further, the main contact 21 of the second relay 2b is closed to conduct the closing circuit of the second breaker 1b, and the second breaker 1b is closed. Similarly, the auxiliary contact 22 of the second relay 2b is coupled with the coil 23 of the first relay 2a, and when the auxiliary contact 22 of the second relay 2b is closed (the main contact 21 of the second relay 2b is in an open state) and a potential difference exists between two ends of a coil power supply loop where the auxiliary contact 22 of the second relay 2b is located, a current passes through the coil 23 of the first relay 2a, so that the coil 23 of the first relay 2a can attract the main contact 21 of the first relay 2a to be closed. Further, the closing circuit of the first circuit breaker 1a is turned on, and the first circuit breaker 1a is closed.

With the above arrangement, the interlocking is achieved such that the first relay 2a and the second relay 2b are in opposite states. After the first relay 2a and the second relay 2b are interlocked, only one main contact 21 of one relay 2 is in a conducting state at the same time, and then the switching-on circuits corresponding to the two circuit breakers 1 can only be conducted at the same time, so that the two circuit breakers 1 cannot be closed at the same time, and the first re-interlocking of the electric interlocking device is realized.

As shown in fig. 1 and 2, in some embodiments, the auxiliary contacts 22 of the relay 2 are coupled to the status indicating contacts 12 of the corresponding circuit breaker 1. For example, an end of the auxiliary contact 22 of the first relay 2a remote from the coil 23 of the second relay 2b is coupled to the output side of the status indication contact 12 of the first circuit breaker 1 a. The input side of the first breaker 1a status indication contact 12 is coupled to the control power module 3. When the normal power supply 4, in which the first circuit breaker 1a is located, is not available, the first circuit breaker 1a is opened, the status of the first circuit breaker 1a indicates that the contact 12 is closed, at which time the auxiliary contact 22 of the first relay 2a is closed, and the coil power supply circuit, in which the auxiliary contact 22 is located (in which the coil is the coil in the second relay 2 b), is turned on. The coil in the second relay 2b is energized such that the coil 23 of the second relay 2b engages the main contact 21 of the relay and the closing circuit of the second circuit breaker 1b is conductive, whereby the second circuit breaker 1b is closed. By connecting the auxiliary contacts 22 of the relay 2 in series to the status indicating contacts 12 of the circuit breaker 1, a second re-interlocking of the electrical interlock is achieved, further improving the safety and stability of the electrical interlock.

In some embodiments, the control power module 3 comprises a control power circuit 31, an output of the control power circuit 31 being coupled to an input side of the status indication contact 12 of the circuit breaker 1, the input being coupled to the normal control power supply 6 and the standby control power supply 7. The control power supply circuit 31 includes at least one of a normal control power supply circuit coupled to the normal control power supply 6 and a standby control power supply circuit coupled to the standby control power supply 7. The common control power supply 6 and the standby control power supply 7 are mutually independent, so that the standby control power supply 7 can be switched to supply power to the coil power supply circuit when the common control power supply 6 is not available.

In some embodiments, the source of the common control power supply 6 may be the same as the source of the common power supply 4 to which the circuit breaker 1 is coupled, and the backup control power supply 7 may be the same as the source of the backup power supply 5 to which the circuit breaker 1 is coupled, but the number of phases of the circuit may be different. For example, the common power source 4 and the standby power source 5 may be three-phase alternating power sources, and the common control power source 6 and the standby control power source 7 may be two-phase alternating power sources.

The control power circuit 31 may supply power to the input side of the status indication contact 12. When the normal power supply 4 fails and is not available, the first circuit breaker 1a coupled to the normal power supply 4 is opened, the state indication contact of the first circuit breaker 1a is closed, and the control power circuit 31 supplies power to the coil 23 of the second relay 2b through the state indication contact of the first circuit breaker 1a and the auxiliary contact 22 of the first relay 2a, so as to control the main contact 21 of the second relay 2b to be attracted. Thereby, the closing circuit in which the second circuit breaker 1b is located is turned on, and the second circuit breaker 1b is closed. Thereby completing the switching from the normal power supply 4 to the standby power supply 5.

As shown in fig. 1 and 2, in other embodiments, the control power module 3 further includes a power supply selection unit 32, the power supply selection unit 32 being coupled between the control power supply circuit 31 and the main contacts 21 of the pair of relays 2, so that the power supply selection unit 32 can also supply power to the closing control coils of the first circuit breaker 1a or the second circuit breaker 1b (in case the main contacts 21 of the corresponding relays 2 are closed) via the closing control ports 11 of the first circuit breaker 1a or the second circuit breaker 1 b.

In other embodiments, the electrical interlock device further comprises a micro-control unit 8 and a pair of transistors 9 (hereinafter also referred to as a first transistor 9a and a second transistor 9 b) respectively coupled in a pair of coil power supply loops. The micro control unit 8 further comprises a power detection port adapted to detect the availability of the common power source and the backup power source, for example to detect whether the common power source 4 where the first circuit breaker 1a is located and the backup power source 5 where the second circuit breaker 1b is located are available. In some embodiments, the power detection port may be coupled to the control power circuit 31 and adapted to receive a power operation signal of the control power circuit 31, the power operation signal including availability of the common control power supply 6 and the backup control power supply 7.

In some embodiments, the micro control unit 8 further comprises a pair of output ports. A pair of output ports is adapted to output either a high level signal or a low level signal depending on the detected availability of the utility power source 4 and the backup power source 5. For example, when the micro control unit 8 receives that the common power supply 4 is not available, the second output port is controlled to output a high level signal, and at this time, the base of the second triode 9b located at the second output port is turned on after receiving the high level signal, so that the coil power supply circuit of the second relay 2b is turned on. And the second breaker 1b is closed. Similarly, when the first circuit breaker 1a needs to be switched on, the micro control unit 8 is required to control the first diode 9a to be switched on, so that a switching-on circuit where the coil 23 of the first relay 1a is located is switched on, and the first circuit breaker 1a is switched on.

As shown in fig. 1 and 2, in some embodiments, the micro control unit 8 further comprises a control signal output port. The control signal output port is coupled to the power supply selection unit 32. The micro control unit 8 controls the power supply selection unit 32 to select the common control power supply 6 or the standby control power supply 7 to supply power to the coil power supply circuit and the closing control coils of the circuit breakers through the control signal output port according to the power supply working signal received from the control power supply circuit 31, so as to respectively control the on-off operation of the two circuit breakers.

As can be seen from the above description, the electrical interlocking device has a simple structure, that is, the two circuit breakers can be interlocked only by two relays with auxiliary contacts, and double electrical interlocking can be realized, and even if one electrical interlocking fails due to device failure, the second electrical interlocking still exists, so that the reliability is high. In addition, the state indication contact of the circuit breaker is connected to the electric interlocking system by the electric interlocking device, and the electric interlocking device is connected with a safe extra-low voltage instead of a power grid voltage, so that the safety is good.

The foregoing description of implementations of the present disclosure has been provided for illustrative purposes, is not exhaustive, and is not limited to the implementations disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various implementations described. The terminology used herein was chosen in order to best explain the principles of each implementation, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand each implementation disclosed herein.

Claims (8)

1. An electrical interlock for a transfer switch system comprising a pair of circuit breakers (1) for controlling the switching of a common power supply circuit and a backup power supply circuit, respectively, characterized in that it comprises:

A pair of relays (2), each relay (2) of the pair of relays (2) comprising:

A main contact (21) coupled to a closing control port (11) of a corresponding circuit breaker (1) of said pair of circuit breakers (1) and adapted to allow, after closing, the circuit breaker (1) to close a power circuit in which it is located;

-a coil (23) arranged to close the main contact (21) after energizing; and

Auxiliary contacts (22) arranged to be connected with the other relay (2)

The coils (23) of one relay (2) are connected in series to form part of a coil supply circuit and are in anti-phase with the on-off state of the main contact (21) of the relay (2) in which they are located; and

-A control power module (3) coupled to the coil supply loop and adapted to allow power to be supplied to the coil (23) in the coil supply loop in case the auxiliary contact (22) is closed.

2. The electrical interlock device according to claim 1, characterized in that the auxiliary contact (22) of each relay (2) is coupled to a status indication contact (12) of the corresponding circuit breaker (1), the on-off state of the status indication contact (12) being in anti-phase with the on-off state of the circuit breaker (1) at which it is located.

3. The electrical interlock according to claim 2, characterized in that the control power module (3) comprises:

-a control power supply circuit (31), the input of the control power supply circuit (31) being coupled to a common control power supply (6) and to a standby control power supply (7), and the output of the control power supply circuit (31) being coupled to the status indication contacts (12) of the pair of circuit breakers (1).

4. An electrical interlock device according to claim 3, wherein the control power module (3) further comprises:

A power supply selection unit (32) coupled between the control power supply circuit (31) and the main contact (21) of the relay (2) and adapted to supply at least the closing control coil of the circuit breaker (1) via the closing control port (11).

5. The electrical interlock of claim 4 further comprising:

A micro control unit (8) comprising:

a pair of output ports adapted to output a high level signal or a low level signal; and a pair of triodes (9), wherein the bases of the triodes (9) are respectively coupled to the output ports of the micro control unit (8), the collectors are respectively coupled to the coil power supply loop, and the emitters are grounded.

6. The electrical interlock device according to claim 5, characterized in that said micro-control unit (8) further comprises:

A power detection port coupled to the control power circuit (31) and adapted to receive a power operation signal of the control power circuit (31).

7. The electrical interlock device according to claim 6, wherein the micro control unit (8) further comprises:

A control signal output port coupled to the power supply selection unit (32) and adapted to output a control signal to the power supply selection unit (32) in accordance with the power supply operation signal to cause a corresponding one of the normal control power supply and the standby control power supply to supply power to the relay.

8. A transfer switch system, comprising:

a pair of circuit breakers (1) respectively coupled to two independent power sources and respectively comprising:

A closing control port (11) adapted to control at least the conduction of said circuit breaker (1), and

A status indication contact (12) arranged with an on-off state opposite to the on-off state of the circuit breaker (1) in which it is located; and

The electrical interlock device according to any one of claims 1-7, being coupled between the pair of circuit breakers (1).