WO2022148539A1

WO2022148539A1 - Power system, circuit breaker and controlling method thereof

Info

Publication number: WO2022148539A1
Application number: PCT/EP2021/050216
Authority: WO
Inventors: Xing Huang; Xiaobo Yang
Original assignee: Hitachi Energy Switzerland Ag
Priority date: 2021-01-08
Filing date: 2021-01-08
Publication date: 2022-07-14

Abstract

A circuit breaker (100) comprises a contact pair (10), at least one contact of the contact pair being a movable contact, the movable contact being able to be moved between an open position corresponding to an open state of the circuit breaker and a closed position corresponding to a closed state of the circuit breaker; a motor-operated actuator (20) coupled with the contact pair and configured to actuate a movement of the movable contact; and a controller (30) configured to control the motor-operated actuator (20) so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker.

Description

Power System, Circuit breaker and Controlling Method thereof

Technical Field

The disclosure relates to a circuit breaker, a method for controlling the circuit breaker and a power system comprising the circuit breaker.

Background

Circuit breakers are widely used in electric plants, such as switching stations, for breaking the power when necessary. The opening or closing of a circuit breaker is achieved through contacts in a breaker chamber. Control means for the contacts traditionally employ a spring mechanical system which stores enough energy for the opening and closing operations.

However, a spring-operated breaker is not completely satisfactory. For example, movements of a movable contact are entirely controlled by the mechanical characteristics of the spring and movement-transfer mechanism. The movement pattern of the movable contact cannot be changed flexibly, as it is predetermined by the device's design. The use of a spring-loaded operating device also incorporates poor precision, as the device is made of a relatively large number of components. As a result of the large number of components, initial adjustment of the operating means, a complex and time-consuming procedure, is also necessary.

Summary of the Invention

This Summary is provided to introduce a group of concepts that are further described below in the Detailed Description. It is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

According to an embodiment, there provides a circuit breaker comprising a contact pair, at least one contact of the contact pair being a movable contact, the movable contact being able to be moved between an open position corresponding to an open state of the circuit breaker and a closed position corresponding to a closed state of the circuit breaker; a motor-operated actuator coupled with the contact pair and configured to actuate a movement of the movable contact; and a controller configured to control the motor-operated actuator so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker.

According to an embodiment, there provides a power system comprising the circuit breaker as described above.

According to an embodiment, there provides a method for controlling the circuit breaker as described above. The method comprises controlling the actuator of the circuit breaker so as to adjust a movement of the movable contact of the circuit breaker during the opening or closing of the circuit breaker.

According to an embodiment, there provides a method for controlling a circuit breaker, the circuit breaker comprising a contact pair, at least one contact of the contact pair being a movable contact, the movable contact being able to be moved between an open position corresponding to an open state of the circuit breaker and a closed position corresponding to a closed state of the circuit breaker; and a motor-operated actuator coupled with the contact pair and configured to actuate a movement of the movable contact, the method comprising controlling the actuator based on detected signals indicating a state of the circuit breaker so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker.

According to an embodiment, there provides a computer program for controlling a circuit breaker, the computer program comprising computer program code which, when executed on a controller, causes the controller to perform the method as described above.

According to an embodiment, there provides a computer readable medium in which instructions are stored, the instructions, when executed by at least one processor, being able to perform the method as described above.

According to embodiments of the disclosure, various travel curves and speeds of the movable contact of the circuit breaker can be realized, and thus the switching time of the circuit breaker can be reduced, and stability and reliability of the circuit breaker can be improved. Other advantages of the disclosure would be explained in the following description.

Brief Description of the Drawings

The disclosed aspects will hereinafter be described in connection with the appended drawings that are provided to illustrate and not to limit the disclosed aspects. Figure l is a schematic block diagram of a circuit breaker according to a possible embodiment of the disclosure.

Figure 2 schematically illustrates an exemplary operating procedure of a circuit breaker according to one possible embodiment of the disclosure.

Figure 3 schematically illustrates the displacement of contact A and /or contact B in normal operation.

Figures 4~7 schematically illustrate displacements of contact A and /or contact B in fault conditions.

Figure 8 schematically illustrates an exemplary operating procedure of a circuit breaker according to another possible embodiment of the disclosure.

Detailed Description of Preferred Embodiments

Some possible embodiments of the disclosure will be described now.

One aspect of the disclosure relates to a circuit breaker which is driven by a motor operated actuator. Figure 1 schematically illustrates a circuit breaker 100 according to a possible embodiment of the disclosure. The circuit breaker 100 mainly comprises a contact pair 10, a motor-operated actuator 20 and a controller 30.

At least one contact of the contact pair 10 is a movable contact (i.e., a mobile contact). The movable contact is able to be moved between an open position corresponding to an open state of the circuit breaker 100 and a closed position corresponding to a closed state of the circuit breaker 100.

In an example, one contact of the contact pair is movable and another contact of the contact pair is stationary (fixed). In the case that one contact is movable and another contact is fixed, the opening speed during the opening operation of the circuit breaker 100 is an absolute speed between the movable contact and the fixed contact. Similarly, the closing speed during the closing operation of the circuit breaker 10 is an absolute speed between the movable contact and the fixed contact. During the opening or closing operation of the circuit breaker 100, the movable contact is driven by the motor-operated actuator 20 such that the movable contact is brought into contact with or separated from the fixed contact.

In another example, both of the contacts of the contact pair are movable. In the case that the two contacts are movable, the opening speed during the opening operation of the circuit breaker 100 is a relative speed between the two movable contacts. Similarly, the closing speed during the closing operation of the circuit breaker 100 is a relative speed between the two movable contacts. During the opening or closing operation of the circuit breaker 100, both of the movable contacts are driven by the motor-operated actuator 20 such that the two movable contacts are moved toward each other or moved away from each other.

The circuit breaker 100 may be a gas-insulated circuit breaker, an electric circuit breaker or a vacuum circuit breaker.

The motor-operated actuator 20 is used as a driving unit for driving the movable contact. The motor-operated actuator 20 is coupled with the contact pair and configured to actuate a movement of the movable contact.

In an example, the motor-operated actuator 20 may comprise a mechanic actuating mechanism coupled with a motor. The motor is an electrical motor, preferably a rotating, electrical motor. The mechanic actuating mechanism is coupled with the movable contact and configured to operate the movable contact. For example, the mechanic actuating mechanism is driven by the motor and configured to transfer energy to the movable contact such that the movable contact is moved between the open position and the closed position.

The controller 30 is configured to control the actuator 20 so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker 100. The controller 30 may comprise a controlling logic for adjusting a travel curve and moving speed of the movable contact. For example, the controller 30 is configured to control running directions of the motor such that the travel curve of the movable contact can be adjusted. The controller 30 is configured to control a running speed of the motor such that the moving speed of the movable contact can be adjusted.

The controller 30 may be integrated with the motor-operated actuator 20. For example, the controller 30 is disposed in a housing of the motor-operated actuator 20. Placing the controller 30 in the housing of the actuator 20 results in that the controller has good protection against electromagnetic interference.

Continuing with reference to Figure 1, the circuit breaker 100 may further comprise one or more sensors. For example, the circuit breaker 100 may further comprise at least one of a travel sensor 40, an angle sensor 50 and an accelerometer 60. Sensing results of the sensors can be used to determine the travel curve and/or speed of the movable contact.

In an example, the travel sensor 40 is coupled with the movable contact. For example, an example of such a travel sensor 40 is a contact travel sensor. Such a contact travel sensor is capable of tracking the position of the movable contact as it moves from the open position to the closed position, and vice versa. The travel curve and speed of the movable contact are determined based on measuring results of the travel sensor 40. For example, the controller 30 receives the measuring results and calculates the travel curve and speed of the movable contact based on measuring results.

In an example, the motor is a rotating electrical motor. The axial position of the rotating electrical motor may be sensed by the angle sensor 50, and the axial position may be used to indicate a linear position of the movable contact. Different positions of the movable contact may be used to indirectly measure the linear speed of the movable contact. For example, the controller 30 receives sensing results of the angle sensor 50 and calculates the speed of the movable contact based on the sensing results. An example of such an angle sensor 50 is a rotary variable differential transformer (RVDT). The RVDT is an inductive transducer which converts an angular displacement to an electrical signal.

In an example, the accelerometer 60 is coupled with the movable contact for measuring an acceleration of the movable contact. The travel curve and speed of the movable contact are determined based on measuring results of the accelerometer 60. For example, the controller 30 receives the measuring results and calculates the travel curve and speed of the movable contact based on measuring results.

The circuit breaker 100 may further comprise a device for detecting a current which passes through the circuit breaker 100 and a device for judging whether the detected current is higher than a current threshold.

In an example, the circuit breaker 100 further comprises a current detecting device (e.g., a current sensor) 70 and a comparator (not shown). The current detecting device 70 is configured to detect a current which passes through the circuit breaker 100. The current detecting device 70 may be disposed in the circuit breaker 100. It has the advantages of a fast detection and short communication latency. The comparator is configured to receive the detected current from the current detecting device 70, judge whether the detected current is higher than a current threshold, and generate an overcurrent signal in the case that it is judged the detected current is higher than the current threshold. The comparator may be disposed in the controller 30, for example, the comparator is a functional module of the controller 30.

It is noted that the current measurement may be handled by an external device (outside of the circuit breaker 100, for example, a grid operator) and then measurement results are transmitted to the controller 30 from the external device. According to examples of the present disclosure, movements of the movable contact can be controlled in a precise and flexible way because the movable contact is driven by the motor-operated actuator. The travel curve and motion of the movable contact can be controlled to realize faster switching and to deal with failures in the circuit breaker 100.

For the purpose of monitoring the state of the circuit breaker 100, a protection system may be used to detect state signals of the circuit breaker 100, and generate a fault signal when it is determined a failure has occurred in the circuit breaker 100. The failure may be cause by overvoltage, overcurrent, hardware failure, software failure, or physical damage.

Figure 2 illustrates one exemplary operating procedure of the circuit breaker 100. In the example illustrated in Figure 2, both of the contacts (i.e., contact A and contact B) of the contact pair are movable. The opening procedure of circuit breaker 100 includes two time periods, i.e., A tl and A t2. In the time period A tl, the contact A and the contact B are driven to move towards each other until they contact each other, i.e., the two contacts are moved from an open position (corresponding to the original position shown in Figures 3~7) to a contacting position (corresponding to the initial contacting position shown in Figures 3~7). For example, the contact A is moved by a distance L A and the contact B is moved by a distance L B. In the time period At2, the contacts A and B are driven to move for a further distance, where the contact A and the contact B overlap with each other, to ensure a reliable engagement of the two contacts. Then, the two contacts reach a closed position (corresponding to the final position shown in Figures 3~7) which corresponds to the closed state of the circuit breaker 100. The closing procedure of the circuit breaker 100 includes two time periods, i.e., Dΐ3 and At4. In the time period At3, the contacts A and B are driven to move away from each other until they reach the contacting position. In the time period At4, the contacts A and B are driven to move to the open position which corresponds to the open state of the circuit breaker 10.

Various travel curves of the movable contact are designed for dealing with failures in the circuit breaker 100. Examples of dynamic control for realizing various travel curves linked with fault scenarios will be described below with reference to the appended drawings.

For the sake of clarity, the displacement of contact A and/or contact B in normal operation is illustrated in Figure 3. In Figure 3, an open-close procedure in normal operation is illustrated. With reference to Figure 3, the movable contact is moved from the original position (the open position) to a contacting position and to reach the contacting position at the time TL The movable contact is then moved to an overlap position and to reach the final position at the time T2, and the circuit breaker 100 is brought into the closed state.

It is noted that, in Figure 3 as well as Figures 4~7, the vertical axis represents positions of the movable contact and the horizontal axis represents time. In the case that one of contact A and contact B is movable, the curve in the figures represents the displacement of the movable contact. In the case that both of contact A and contact B are movable, the curve in the figures represents the displacement of either one of contact A and contact B.

Figure 4 illustrates the displacement of contact A and/or contact B in a fault condition (e.g. fault condition 1).

With reference to Figure 4, in the case that the controller 30 receives a fault signal from the protection system during the closing operation of the circuit breaker 10, the controller 30 is configured to control the actuator 20 such that the movable contact is stopped before reaching the closed position and then is moved to the open position.

For example, the movable contact is moved to reach the contacting position at the time Til and moved to reach a position before the final position at the time T12. The controller 30 receives a fault signal at the time T12 after the time Til (e.g. during the time period At2). The controller 30 is configured to generate a control signal in response to receiving the fault signal. Under the control of the control signal, the movable contact is stopped before reaching the final position (i.e., the distance of the overlap in Figure 4 is smaller than that of the overlap in Figure 3), and then an opening procedure is initiated. The movable contact is moved to reach the original position (the open position) at the time T13.

It is seen that, during the closing operation of the circuit breaker 100, once the controller 30 receives a fault signal, the whole closing travel will not be completed and an opening procedure will be initiated. In this way, the close-open time is decreased in the case of a fault occurring during the closing operation of the circuit breaker 100.

Figure 5 illustrates the displacement of contact A and/or contact B in a fault condition (e.g. fault condition 2).

With reference to Figure 5, the movable contact is moved to reach an intermediate position 1, which is between the open position and the contacting position, at the time T21, and the controller 30 receives a fault signal at the time T21 (e.g., during the time period Dΐΐ). The controller 30 is configured to generate a control signal in response to receiving the fault signal. Under the control of the control signal, the movable contact is moved in a direction to increase the distance between contacts A and B until the movable contact is moved to reach an intermediate position 2, which is nearer to the open position than the intermediate position 1, at the time T22. The movable contact is then moved in an opposition direction to decrease the distance between contacts A and B until the movable contact is moved to approach the contacting position at the time T23, and the controller 30 is configured to generate a further control signal according to a fail-safe mechanism. The movable contact is moved to the open position (i.e., the original position) under the control of the further control signal. The movable contact is moved to reach the open position at the time T24.

Figure 6 illustrates the displacement of contact A and/or contact B in a fault condition (e.g. fault condition 3).

With reference to Figure 6, the movable contact is moved to reach an intermediate position 1, which is between the open position and the contacting position, at the time T31, and the controller 30 receives a fault signal at the time T31 (e.g., during the time period Dΐΐ). The controller 30 is configured to generate a control signal in response to receiving the fault signal. Under the control of the control signal, the movable contact is moved in a direction to increase the distance between contacts A and B until the movable contact is moved to reach an intermedia position 2, which is nearer to the open position than the intermediate position 1, at the time T32. The movable contact is then moved in an opposition direction to decrease the distance between contacts A and B until the movable contact is moved to approach the contacting position at the time T33, and the controller 30 is configured to generate a further control signal. The movable contact is moved to the closed position (i.e., the final position) under the control of the further control signal. The movable contact is moved to reach the closed position at the time T34.

The example of Figure 6 is different from the example of Figure 5 in that the movable contact is moved to the closed position finally. In this example, the controller 30 may receive an instruction from the protection system and the instrction indicates that the fault has been removed and it is safe to go into the closed state.

According to examples of the disclosure, an arc extinguishing effect (for example, the total arc extinguishing time is reduced when overcurrent occurs) can be obtained by means of controlling movements of the contacts.

In the case that the controller 30 receives an overcurrent signal when arcing occurs, the controller 30 is configured to control the actuator 20 such that the movable contacts are moved towards a direction to decrease the distance between two contacts, optionally, until the two contacts contact with each other, and then are moved towards an opposite direction to increase the distance between the two contacts.

Figure 7 illustrates the displacement of contact A and/or contact B in an overcurrent fault condition (e.g. fault condition 4).

With reference to Figure 7, arcing occurs in the circuit breaker 100 and a short circuit fault is detected at the time T41, (i.e., during the time period Dΐΐ), the short current through the contacts will increase quickly and thus the contacts are damaged seriously. For the purpose of arc extinction, a flow of arc extinguishing fluid may be generated by means of controlling the movements of the contacts.

For example, the controller 30 is configured to generate a control singal in responding to receiving a short circuit fault signal, and the movable contact is moved towards a direction to decrease the distance between the two contacts under the control of the control signal. The movable contact is moved to approach the contacting position at the time T42. This contributes to store energy for pressure buildup in an arc extinguishing fluid. At the time T42, the controller 30 is configured to generate a further control signal, and the movable contact is moved in an opposite direction with a fast speed (for example, the moving speed of the movable contact may be increased by 20%~40% compared to the average opeing speed) to increase the distance between the two contacts unther the further control signal, during which a compression of a gaseous volume of the arc extinguishing fluid may be used for arc interruption. In this way, the buildup of pressure in the arc extinguishing fluid takes place by means of the controlled movements of the contacts without any additional mechanical components or additional arc extinguishing fluids.

According to examples of the disclosure, faster switching operation can be realized by means of controlling movements of the contacts.

In the case that the controller 30 does not receive any fault signals during the closing operation of the circuit breaker 100, the controller 30 is configured to control the actuator 20 such that the movable contact is moved with a speed higher than an average closing speed for part of its whole closing travel and then is decelerated for rest of its whole closing travel, optionally, the deceleration is initiated after two contacts contact with each other.

It is noted that the average closing speed is understood as the average moving speed of the movable contact from the open position to the closed position.

In an example, in an initial stage of the closing procedure, such as 40%~80% of the whole closing travel or the stage wherein the movable contact is moved from the open position to the contacting position, the moving speed of the movable contact may be increased by 20%~40% compared to the average closing speed. For the purpose of reducing collision damage to the movable contact, the moving speed of the movable contact may be decreased when the movable contact is close to the closed position (fixed position). The speed of the movable contact at the closed position may be reduced by a level which is determined based on at least one of the following aspects (1) ~ (3).

(1) A deceleration ability of the circuit breaker 100 is taken into consideration. The deceleration of the movable contact cannot beyond the upper limit of deceleration ability of the circuit breaker 100.

(2) A mechanical stress of the movable contact at the closed position is taken into consideration. When the movable contact reaches the closed position, the speed of the movable contact may not be zero and thus the movable contact is subjected to mechanical stress when the movable contact collides with a stopper at the closed position. The mechanical stress will be reduced with the decreasing in the speed of the movable contact.

(3) A time duration for extinguishing arc in the circuit breaker 100 is taken into consideration. For example, the deceleration is trigged after the two contacts contact with each other, because the arc will be quenched as soon as the contacts contact with each.

Similarly, during the opening operation of the circuit breaker 100, the controller 30 is configured to control the actuator 20 such that the movable contact is moved with a speed higher than an average opening speed for part of its whole opening travel and then is decelerated for rest of its whole opening travel, optionally, the deceleration is initiated after extinguishing arc in the circuit breaker 100.

It is noted that the average opening speed is understood as the average moving speed of the movable contact from the closed position to the open position.

In an example, in an initial stage of the opening procedure, such as 40%~80% of the whole opeing travel, the moving speed of the movable contact may be increased by 20%~40% compared to the average opening speed. For the purpose of reducing collision damage to the movable contact, the moving speed the movable contact may be decreased when the movable contact is close to the open position (fixed position). The speed of the movable contact at the open position may be reduced by a level which is determined based on at least one of the above described aspects (1) ~ (3). Figure 8 illustrates another exemplary operating procedure of the circuit breaker 100. In the example illustrated in Figure 8, both of the contacts (i.e., contact A and contact B) of the contact pair are movable. The closing procedure is illustrated as the time period At Open-Close. In the time period A t Open-Close, the contact A and the contact B are driven to move from the open position to the closed position. The opening procedure is illustrated as the time period At Close-Open In the time period At Close-Open, the contact A and the contact B are driven to move from the closed position to the open position.

See Figure 8, during the time period A t Open-Close, the contact A and the contact B are moved with a moving speed 15% ~ 50% higher than average closing speed for over a half of the whole closing travel, and the moving speed at the closed position is reduced by 15-50% compared to the average closing speed.

Continuing with reference to Figure 8, during the time period A t Close- Open, the contact A and the contact B are moved with a moving speed 15% - 50% higher than average opening speed for over a half of the whole opening travel, and the moving speed at the open position is reduced by 15-50% compared to the average opening speed.

It is seen that the moving speed of the contact of the the circuit breaker 100 according to examples of the disclosure can be adjusted without large mechanical stress compared to a typical circuit breaker driven by a spring mechanical system, and thus switching time of the circuit breaker 100 can be decreased. Moreover, by means of operating the circuit breaker 100 with a motor, various travel curve of the breaker contact for dealing with failures in the circuit breaker 100 are available and thus the lifetime of the circuit breaker is increased.

It is noted that multiple sensors are illustrated in Figure 1; however, the circuit breaker may be implemented with lesser number of sensors or no sensors. For example, the controlling operation may be implemented in an open loop (e.g., no sensor feedback).

In an example, a desired movement (a direction and/or a speed) of the movable contact may be caused by the drive of the motor. For example, the controller may determine a movement of the movable contact based on a detected signal which indicates a state of the circuit breaker, and then determine a current supplied to the motor based on a predetermined motor model, such that the movable contact is moved to implement the determined movement. It is noted that the motor model may include a relationship between a supplied current and a running state of the motor.

It is noted that detected signals (e.g., fault signals, sensor measurement signals), may be received by the controller 30. Alternatively, the detected signals (e.g., fault signals, sensor measurement signals) may also be received by an external device, which is associated with the circuit breaker, and then transmitted to the controller 30 from the external device. An example of such an external device is an Intelligent Electronic Device (IED).

The disclosure in another aspect relates to a power system comprising the circuit breaker 100 as described above. The power system may comprise one or more systems for a power grid, such as a transmission network and a distribution network. According to examples of the disclosure, power grid transient stability and operational resiliency of the power system, which comprises the circuit breaker 100, can be improved.

The disclosure in yet another aspect relates to a method for controlling the circuit breaker 100 as described above. Various features described above with reference to the circuit breaker 100 are also applicable in the method, and thus the description to them is omitted.

The method according to a possible embodiment of the disclosure mainly comprises the step of controlling the actuator 20 so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker 10.

In an example, controlling the actuator 20 so as to adjust a movement of the movable contact during the opening or closing of the circuit breaker comprises controlling the actuator so as to dynamically adjust at least one of a direction and a speed of the movement of the movable contact during the opening or closing of the circuit breaker 100.

In an example, controlling the actuator 20 so as to adjust a movement of the movable contact during the opening or closing of the circuit breaker comprises, in the case that the controller 30 receives a fault signal during the closing operation of the circuit breaker, controlling the actuator 20 such that the movable contact is stopped before reaching the closed position and then is moved to the open position.

In an example, controlling the actuator 30 so as to adjust a movement of the movable contact during the opening or closing of the circuit breaker comprises, in the case that the controller 30 receives a fault signal during the closing operation of the circuit breaker, controlling the actuator 20 such that the movable contact is moved towards a direction to incease the distance between two contacts and then is moved towards an opposite direction to decrese the distance between the two contacts.

In an example, controlling the actuator 30 so as to adjust a movement of the movable contact during the opening or closing of the circuit breaker comprises, in the case that the controller 30 receives an overcurrent signal when arcing occurs, controlling the actuator 20 such that the movable contact is moved towards a direction to decrease the distance between two contacts, optionally, until the two contacts contact with each other, and then is moved towards an opposite direction to increase the distance between the two contacts.

In an example, controlling the actuator 30 so as to adjust a movement of the movable contact during the opening or closing of the circuit breaker comprises, in the case that the controller 30 does not receive any fault signals during the closing operation of the circuit breaker 100, controlling the actuator 20 such that the movable contact is moved with a speed higher than an average closing speed for part of its whole closing travel and then is decelerated for rest of its whole closing travel, optionally, the deceleration is initiated after two contacts contact with each other.

The method according to a possible embodiment of the disclosure mainly comprises the step of controlling the actuator 20 based on detected signals indicating a state of the circuit breaker so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker 100.

It is noted that all the operations in the methods described above are merely exemplary, and the present disclosure is not limited to any operations in the methods or sequence orders of these operations, and should cover all other equivalents under the same or similar concepts.

The disclosure in yet another aspect relates to a computer program for controlling the circuit breaker 100 as described above. The computer program comprises computer program code which, when run on a controller, causes the controller to perform the method described above.

It is noted that the controller may comprise a processor, using any combination of one or more of a suitable central processing unit, CPU, multiprocessor, microcontroller, digital signal processor, DSP, application specific integrated circuit etc., capable of executing software instructions of a computer program stored in a memory. The memory can thus be considered to be or form part of a computer program product. The processor may be configured to execute a computer program stored therein to cause the controller to perform desired steps. The disclosure in yet another aspect relates to a computer readable medium in which instructions are stored, the instructions, when executed by at least one processor, being able to perform the method described above.

It is noted that software should be considered broadly to represent instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, running threads, processes, functions, and the like. Software can reside on computer readable medium. Computer readable medium may include, for example, a memory, which may be, for example, a magnetic storage device (e.g., a hard disk, a floppy disk, a magnetic strip), an optical disk, a smart card, a flash memory device, a random access memory (RAM), a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a register, or a removable disk. Although a memory is shown as being separate from the processor in various aspects presented in this disclosure, a memory may also be internal to the processor (e.g., a cache or a register).

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein. All structural and functional equivalent transformations to the elements of the various aspects of the present disclosure, which are known or to be apparent to those skilled in the art, are intended to be covered by the claims.

Claims

CLAIMS:

1. A circuit breaker (100) comprising: a contact pair (10), at least one contact of the contact pair being a movable contact, the movable contact being able to be moved between an open position corresponding to an open state of the circuit breaker and a closed position corresponding to a closed state of the circuit breaker; a motor-operated actuator (20) coupled with the contact pair and configured to actuate a movement of the movable contact; and a controller (30) configured to control the motor-operated actuator (20) so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker.

2. The circuit breaker (100) as claimed in claim 1, wherein controlling the actuator (20) so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker comprises: controlling the actuator (20) so as to dynamically adjust at least one of a direction and a speed of the movement of the movable contact during the opening or closing operation of the circuit breaker.

3. The circuit breaker (100) as claimed in claim 1 or 2, wherein controlling the actuator (20) so as to adjust a movement of the movable contact comprises: in the case that the controller (30) receives a fault signal during the closing operation of the circuit breaker, controlling the actuator (20) such that the movable contact is stopped before reaching the closed position and then is moved to the open position.

4. The circuit breaker (100) as claimed in any one of claims 1—3, wherein controlling the actuator (20) so as to adjust a movement of the movable contact comprises: in the case that the controller (30) receives a fault signal during the closing operation of the circuit breaker, controlling the actuator (20) such that the movable contact is moved towards a direction to incease the distance between two contacts and then is moved towards an opposite direction to decrese the distance between the two contacts.

5. The circuit breaker (100) as claimed in any one of claims 1~4, wherein controlling the actuator (20) so as to adjust a movement of the movable contact comprises: in the case that the controller (30) receives an overcurrent signal when arcing occurs, controlling the actuator (20) such that the movable contact is moved towards a direction to decrease the distance between two contacts, optionally, until the two contacts contact with each other, and then is moved towards an opposite direction to increase the distance between the two contacts.

6. The circuit breaker (100) as claimed in any one of claims 1-5, wherein controlling the actuator (20) so as to adjust a movement of the movable contact comprises: in the case that the controller (30) does not receive any fault signals during the closing operation of the circuit breaker (100), controlling the actuator (20) such that the movable contact is moved with a speed higher than an average closing speed for part of its whole closing travel and then is decelerated for rest of its whole closing travel, optionally, the deceleration is initiated after two contacts contact with each other.

7. The circuit breaker (100) as claimed in claim 6, wherein the speed of the movable contact at the closed position is reduced by a level which is determined based on at least one of:

- a deceleration ability of the circuit breaker (100);

- a mechanical stress of the movable contact at the closed position;

- a time duration for extinguishing arc in the circuit breaker (100).

8. The circuit breaker (100) as claimed in any one of claims 1-7, wherein controlling the actuator (20) so as to adjust a movement of the movable contact comprises: during the opening operation of the circuit breaker (100), controlling the actuator (20) such that the movable contact is moved with a speed higher than an average opening speed for part of its whole opening travel and then is decelerated for rest of its whole opening travel, optionally, the deceleration is initiated after extinguishing arc in the circuit breaker (100).

9. The circuit breaker (100) as claimed in claim 8, wherein the speed of the movable contact at the open position is reduced by a level which is determined based on at least one of:

- a deceleration ability of the circuit breaker (100);

- a mechanical stress of the movable contact at the open position;

- a time duration for extinguishing arc in the circuit breaker (100).

10. The circuit breaker (100) as claimed in any one of claims 1-9, wherein the circuit breaker (100) further comprises an angle sensor (50) coupled to a motor, which is assocaiated with the motor-operated actuator (20), for measuring a rotation angle of the motor; and the travel curve and speed of the movable contact are determined based on measuring results of the angle sensor (50).

11. The circuit breaker (100) as claimed in any one of claims 1-10, wherein the circuit breaker (100) further comprises a travel sensor (40) coupled with the movable contact for measuring a travel of the movable contact, and the travel curve and speed of the movable contact are determined based on measuring results of the travel sensor (40).

12. The circuit breaker (100) as claimed in any one of claims 1-11, wherein the circuit breaker (100) further comprises an accelerometer (60) coupled with the movable contact for measuring an acceleration of the movable contact, and the travel curve and speed of the movable contact are determined based on measuring results of the accelerometer (60).

13. The circuit breaker (100) as claimed in any one of claims 1-12, wherein the circuit breaker (100) further comprises: a current detecting device (70) configured to detect a current which passes through the circuit breaker (100); and a comparator configured to receive the detected current, judge whether the detected current is higher than a current threshold, and generate an overcurrent signal in the case that it is judged the detected current is higher than the current threshold, optionally, the comparator is disposed in the controller (30).

14. The circuit breaker (100) as claimed in any one of claims 1-13, wherein the circuit breaker (100) is selected from a group of a gas-insulated circuit breaker, an electric circuit breaker and a vacuum circuit breaker.

15. A power system comprising a circuit breaker (100) as described in any one of claims 1-14.

16. A method for controlling a circuit breaker (100) as described in any one of claims 1-14, the method comprising: controlling the actuator (20) of the circuit breaker (100) so as to adjust a movement of the movable contact of the circuit breaker (100) during the opening or closing operation of the circuit breaker (100).

17. A method for controlling a circuit breaker (100), the circuit breaker (100) comprising a contact pair (10), at least one contact of the contact pair being a movable contact, the movable contact being able to be moved between an open position corresponding to an open state of the circuit breaker and a closed position corresponding to a closed state of the circuit breaker; and a motor-operated actuator (20) coupled with the contact pair and configured to actuate a movement of the movable contact, the method comprising: controlling the actuator (20) based on detected signals indicating a state of the circuit breaker so as to adjust a movement of the movable contact during the opening or closing operation of the circuit breaker (100).

18. A computer program for controlling a circuit breaker (100), the computer program comprising computer program code which, when executed on a controller, causes the controller to perform the method of claim 16 or 17.

19. A computer readable medium in which instructions are stored, the instructions, when executed by at least one processor, being able to perform the method of claim 16 or 17.