Circuit breaker

Abstract

A circuit breaker device (100) includes a circuit breaker (110), a motor drive system (120), and a controller (150). The circuit breaker (110) is electrically connected to a power line (115). The motor drive system (120) is mechanically coupled to the circuit breaker (110) and configured to operate the circuit breaker (110), such as performing a disconnecting motion including at least a closed position to an open position, thereby electrically interrupting the power line (115). The controller (150) includes a model (155) of at least one of the motor drive system (120) and the circuit breaker (110). The controller (150) is configured to: receive reference stroke curve information (200) of the motion; generate actuator information (210) from the reference stroke curve information (200) based on the model (155); and output the actuator information (210) to the motor drive system (120) to control the stroke curve through model-based control.

Description

Technical Field

[0001] This disclosure relates to a circuit breaking device. In particular, it relates to a circuit breaking device including an electric motor drive that controls circuit breakers used for generators in power plants, such as circuit breakers rated for commonly used nominal currents in the field of generators in power plants, such as nominal currents of 63 kA or greater. Background Technology

[0002] Circuit breakers configured for use with generators in power plants are designed as switches, i.e., to disconnect or connect large currents ranging from tens to hundreds of kiloamperes flowing in power lines. Some circuit breaking equipment includes such circuit breakers as well as motor drive systems configured to operate the circuit breakers.

[0003] A portion of the motor drive system is mechanically coupled or connected to a circuit breaker and configured to operate the circuit breaker. Typically, operation includes performing at least one of the circuit breaker's opening and closing movements. In the opening movement, for example, the relevant portion of the circuit breaker moves from the closed position to the open position, thus electrically interrupting the power line.

[0004] In this disconnection motion, the motion characteristics of the circuit breaker are described by controlling the motor drive system.

[0005] In some configurations, it can also facilitate the control of the circuit breaker's stroke curve during the closing motion. Summary of the Invention

[0006] Provide circuit breaker equipment based on one aspect.

[0007] In this embodiment, the circuit breaking device includes a circuit breaker, a motor drive system, and a controller.

[0008] Circuit breakers can be electrically connected to power lines. For example, a circuit breaker has an input terminal and an output terminal, and it can be connected between power lines. Power lines are lines used for the transmission of electricity. For example, a power line can be the output line on the primary or secondary side of a transformer, or it can be the output line of a generator (such as a generator in a power plant).

[0009] The motor drive system is mechanically connected to the circuit breaker. As used herein, the mechanical connection may include an actuating element disposed between the motor of the motor drive system and the actuator of the circuit breaker. For example, the actuating element is a linkage mechanism whose input side is mechanically connected to the output side of the motor and whose output side is mechanically connected to the circuit breaker chamber of the circuit breaker.

[0010] The motor drive system is configured to operate a circuit breaker. Operating the circuit breaker may include, for example, actions performed on elements of the circuit breaker, such as actuators. Movement is typically performed via an actuating member (such as a linkage) connected to the motor drive. The movement includes at least a disconnecting movement of the circuit breaker, moving it from the closed position to the open position. Through the disconnecting movement, the power lines are electrically interrupted. For example, in the open position, a first end of the power line connected to the input and a second end of the power line connected to the output are electrically disconnected from each other.

[0011] The controller includes models of at least one of a circuit breaker and a motor drive system. Typically, the controller includes models of both the motor drive system and the circuit breaker. For example, the model shows the connection between the motor and the linkage, such as the motor torque acting on the linkage, and the connection between the linkage and the circuit breaker, such as the reaction force on the linkage when the actuator of the circuit breaker is operated.

[0012] The controller is configured to receive reference stroke curve information of the motion. The controller is also configured to generate actuator information from the reference stroke curve information based on a model; and output the actuator information to the motor drive system to control the stroke curve through model-based control.

[0013] Typically, the reference travel curve information includes at least information about the disconnection motion. In this example, the controller is configured to: receive the reference travel curve information for the disconnection motion; generate actuator information from the reference travel curve information based on a model for the disconnection motion; and output the actuator information to the motor drive system to control the circuit breaker disconnection travel curve through model-based control. In this embodiment, the reference travel curve information includes reference information about the trajectory and speed.

[0014] In an embodiment, the movement also includes the closing movement of the circuit breaker, moving it to the closed position when it is in the open position. The closing movement electrically connects the power lines. For example, in the closed position, a first end of the power line connected to the input and a second end of the power line connected to the output are electrically connected to each other. In such an embodiment, for example, the controller is further configured to: receive reference stroke curve information of the closing movement; generate actuator information from the reference stroke curve information based on a model for the closing movement; and output the actuator information to the motor drive system to control the circuit breaker closing stroke curve through model-based control.

[0015] As used herein, model-based control may include performing model predictive control, such as, but not limited to, dynamic matrix control, model algorithmic control, linear quadratic Gaussian control, and / or generalized predictive control.

[0016] In this application, the circuit breaker is not limited to a single-phase configuration. For example, the circuit breaker of the circuit breaker may be electrically connected to a multi-phase power line, such as a three-phase power line.

[0017] As used herein, a reference travel curve may include information about the circuit breaker position and / or speed of movement after a period of time. In embodiments, the reference travel curve includes the time-dependent progression of a reference position of a portion of the motor drive system or circuit breaker. Typically, the reference travel curve includes the time-dependent progression of a reference position (e.g., a desired position) of the circuit breaker at any point in time between the open and closed states of the circuit breaker's actuator or contacts and / or between the closed and open states. It should be noted that the reference position may include intermediate positions, i.e., positions where the circuit breaker is not (not yet) fully open or closed. Additionally or alternatively, the reference travel curve typically includes the time-dependent progression of a reference speed (i.e., a desired speed) of the circuit breaker position at any point in time between the open and closed states of the circuit breaker's actuator or contacts and / or between the closed and open states.

[0018] In one embodiment, the motor drive system includes a motor connected to a linkage. The linkage is configured to convert the rotational motion of the motor into substantially linear motion and output the linear motion to a circuit breaker. The model includes information on the motor torque between the motor and the linkage, as well as information on the reaction force between the linkage and the circuit breaker.

[0019] Optionally, the model may additionally include information on pressure and / or friction dynamics. Pressure dynamics simulates friction occurring in the system, such as friction between a motor and an actuator, friction between an actuator and a circuit breaker, or both. Pressure dynamics simulates air pressure in the system, such as air pressure in the circuit breaker chamber. Pressure dynamics generates the forces that ultimately act on the actuator connected to the chamber.

[0020] In an embodiment, model-based control includes employing an optimized control strategy to mathematically optimize at least one optimization objective in the optimization problem. The optimization objective may be a selection of a position described by reference travel curve information and a speed described by the reference travel curve information. Typically, the position is a reference position of the circuit breaker position at any point in time between the open and closed states of the circuit breaker's actuator or contacts and / or between the closed and open states, e.g., a desired position. Typically, the speed is a reference speed of the circuit breaker position at any point in time between the open and closed states of the circuit breaker's actuator or contacts and / or between the closed and open states, e.g., a desired speed.

[0021] In this embodiment, the controller has an interface with a set of pre-computed control parameters that describe the optimized control strategy. The controller is also configured to perform model-based control using these pre-computed control parameters. Typically, the controller is configured to perform model-based control using the pre-computed control parameters via fast feedforward control and robust feedback control.

[0022] Alternatively or additionally, in this embodiment, the controller is also configured to calculate control parameters describing the optimized control strategy, and to perform model-based control using the calculated control parameters. Typically, the controller is also configured to refresh the control parameters using the calculated control parameters. Typically, the controller is also configured to use model-based control as model predictive control.

[0023] In this embodiment, the optimization problem includes a cost function and at least one constraint equation. The cost function includes an optimization objective. The at least one constraint equation describes the magnitude of change of the circuit breaker device. The magnitude of change varies during movement. Therefore, the threshold for the magnitude of change may include one or more of the following: the separation speed of the circuit breaker contacts when the movement is an opening movement; the approach speed of the circuit breaker contacts when the movement is a closing movement; the temperature inside the circuit breaker chamber; the motor torque; and the linkage force.

[0024] In this embodiment, the controller is also configured to receive operational data related to the model parameters of the model, and to update the model parameters of the model using the received operational data. The operational data may include the behavior of the circuit breaker, such as degradation behavior due to the aging of equipment components. Because the circuit breaker and / or its components degrade over their lifespan, the operational data can be used to update or adopt a model of the current state of the equipment.

[0025] In this embodiment, the circuit breaker is a generator circuit breaker used in a power plant's generator. Typically, this generator circuit breaker is rated for a nominal current of 63 kA or greater. Attached Figure Description

[0026] Embodiments of this disclosure will be described with reference to the accompanying drawings, in which:

[0027] Figure 1 This is a block diagram illustrating an overview of the configuration of a circuit breaker according to an embodiment;

[0028] Figure 2 It is by Figure 1 A block-based flowchart detailing the control details executed by the controller of the circuit breaker; and

[0029] Figure 3This is an example of a travel curve used in model-based control executed by the controller. Detailed Implementation

[0030] The general overview of the technology and embodiments of the present disclosure will now be described with reference to the accompanying drawings.

[0031] Figure 1 This is a block diagram illustrating the configuration of the circuit breaker 100. Figure 1 In this circuit, the motor drive system 120 is mechanically coupled to the circuit breaker 110. The circuit breaker 110 has terminals (not shown) connected between power lines 115 (high-voltage lines) and is configured to selectively interrupt and / or close the electrical connection on the power lines 115. To perform such an action, the motor drive system 120 operates the circuit breaker 110 between the open and closed positions and / or between the closed and open positions.

[0032] The motor drive system 120 includes a motor 130 and a linkage 140. The motor 130 is configured to apply motor torque Torque to the linkage 140. mot The linkage 140 is configured to convert rotational motion received from the input side of the motor 130 into substantially linear motion and to output substantially linear motion from the output side of the motor 130. The linkage 140 is connected to the circuit breaker 110 and transmits force or torque from the motor to the circuit breaker 110. The circuit breaker 110 typically includes a circuit breaker chamber in which circuit breaker electrical contacts are disposed to perform effective interruption and / or closing selection of electrical connections. Typically, an actuating element (not shown) is disposed on the circuit breaker 110 to establish a mechanical interconnection between the circuit breaker contacts and the linkage 140. Hereinafter, the motor 130, the linkage 140, and the circuit breaker chamber 110 may be collectively referred to as mechanical body 160.

[0033] The controller 150 is configured to control the movement or action of the motor 130. Figure 1 In the example shown, the controller outputs the required torque Torque to motor 130. req .exist Figure 1 In this circuit, controller 150 is a closed-loop controller. Signals indicating the motor speed and position of motor 130 are fed back to controller 150.

[0034] Ideally, the motor drive system 120 controls the movement of the circuit breaker 110 or the indirect movement of the circuit breaker contacts, thereby following a reference travel curve. In conventional systems without a motor drive, there is no possibility of controlling the movement of the circuit breaker during the opening or closing movement of the circuit breaker contacts.

[0035] The introduction of the motor drive system 120 makes it possible to further control the degrees of freedom of the circuit breaker, for example, to improve its robustness, lifespan, and health status. Typically, the configuration of the stroke curve of the motor drive system 120 involves a control system-based approach. That is, in a typical configuration, the stroke curve of the motor drive system 120 is divided into multiple consecutive stages. The tracked reference curve is configured for each of these consecutive stages. Furthermore, the transition criteria used to move from one stage to the next in the multiple consecutive stages are defined from a control system perspective. The controller itself includes three separate PI controllers connected in series. The first PI controller controls the position of the circuit breaker contacts. The second PI controller controls the speed of movement of the circuit breaker contacts. The third PI controller controls the torque applied to the linkage system by the motor. Transitions are typically defined by target thresholds, such as speed thresholds, position thresholds, or time thresholds.

[0036] In traditional methods, the PI controller and target thresholds for the transition must be defined for the circuit breaker, which is not intuitive for circuit breaker engineers and therefore requires system designers with comprehensive knowledge of control systems. Furthermore, the configuration of the stroke curve is limited to a predetermined number of stages, typically six, with fixed control parameters assigned to each stage. Direct stroke curve optimization is not possible in traditional techniques.

[0037] Figure 2 It is by Figure 1 The basic module flowchart of the control details executed by the controller of the circuit breaker. Figure 3 This is an example of a stroke curve used in model-based control executed by the controller. See below for reference. Figures 1-3 Describe it.

[0038] In the technology according to this disclosure, controller 150 includes model 155. Model 155, or its mathematical description, depicts the relevant physical phenomena that affect the movement of the control circuit breaker. Controller 150 receives reference stroke curve information 200 of the movement. Figure 3 An example of a stroke curve that can be derived from appropriate reference stroke curve information 200 is illustrated and will be described below. Controller 150 generates actuator information 210 from the reference stroke curve information 200. To generate actuator information 210, the controller employs model 155; that is, actuator information 210 is based on model 155. Controller 150 outputs actuator information 210 to motor drive system 120 to control the stroke curve of the movement of circuit breaker 110 or a portion thereof. This control is accomplished through model-based control.

[0039] Model-based control is a control method that is generally known to those skilled in the art. For example, the paper "Optimal LQG Controller for Variable Speed ​​Wind Turbine Based on Genetic Algorithms" by Barrera-Cardenas R and Molinas M, Energy Procedia 20 (2012), 207-216, presents a model-based control method in the wind turbine section. As another example, the paper "Fast Model Predictive Control Combining Offline Method and Online Optimization with KD Tree" by Ding Y, Xu Z, Zhao J, and Shao Z, accessible via DocumentOnline Identifier at http: / / dx.doi.org / 10.1155 / 2015 / 982041, describes application cases of model predictive control, which is a model-based control method under specific conditions of computability.

[0040] Model-based control addresses the fact that, for example, the torque applied from motor 130 to linkage 140, such as during a disconnecting motion, is not always transmitted to the output side of the linkage due to variations in the current flowing through the circuit breaker contacts and the force required to separate the contacts. Furthermore, friction and pressure are not always the same across multiple operations; that is, the increase in pressure varies, and the system's inertia is not linear. Model-based control can still maintain the reference stroke curve to an appropriate degree because it possesses "knowledge" of the system's dynamics.

[0041] Model-based control, such as model predictive control (MPC), can include, but is not limited to, control methods employed, referred to as dynamic matrix control (DMC), model algorithmic control (MAC), and generalized predictive control (GPC).

[0042] In the model-based control of current circuit breaker devices, a model of a system, such as a motor drive and a circuit breaker, is created. One or more optimization objectives, such as travel curves, are described as mathematical conditions. The solution to one or more optimization objectives is a control strategy for a motor drive system 120, which is controlled by a controller 150 having a model 155.

[0043] According to one aspect, the model is a linearized system model, and the state-space model is combined into an equality constraint of the form: (x(k+1)=A·x(k)+B·u(k)), where x is the state vector, u is the input vector, A is the state matrix, B is the input matrix, and k is the index variable. Linear model-based control is performed using the linear system model as the model; typically, linear model-based control includes linear model predictive control and MPC. The linear system model can be a constant linear model or a time-varying linear system model. During equipment operation, time-varying linear system models are typically suitable for system characteristics that vary over time, such as the mechanical wear of system components.

[0044] According to another aspect, the model is a nonlinear system model. For example, the dynamics of the circuit breaker system and the anticipated additional inertia, as well as the additional possibilities of the motor drive or its components, such as frictional and pressure variations, are considered as having an equality constraint of the form: (x(k+1)=f(x(k),u(k))), where x is the state vector, u is the input vector, and f is a function containing a nonlinear representation of the circuit breaker, possibly including the motor drive or its components as a nonlinear circuit breaker model. The function f uses an integral method to predict the future system state within the prediction horizon. Typically, the prediction horizon is a backward prediction horizon or a finite backward prediction horizon. As an example, the integral method includes the first-order Euler method (1... st One of the following methods: the Euler method or the Runge-Kutta method.

[0045] From another perspective, Model 155 does not have a classical control system model, such as a state-space model or a transfer function model. Furthermore, compared to state-space models or transfer function models, Model 155 can be a model with lower mathematical accuracy requirements; thus, for example, through model parameter feedback, Model 155 can be updatable or adaptive.

[0046] Model-based control typically relies on an algorithm, and consequently, on a model 155. Typically, in model-based control such as MPC, the control movements generated by the controller 150 on the motor drive system 120 are implemented in a backward, limited-view manner. A cost function is optimized to determine future control movements, where the cost function relates to the future behavior of the system. For example, the cost function minimizes the magnitude of future changes in the output of the controller 150 to the motor drive system 120, with reference to position tracking and / or speed tracking curves.

[0047] Typically, the cost function derives from one or more of the following: the position and speed errors of the desired motion to provide a reference for following; the motor drive to bring the motor to a standstill / stop; and the motor torque deviation to avoid motor damage and / or reduce motor wear. Typically, the cost function is a convex cost function that takes into account constraints, such as finite motor torque and / or finite motor speed.

[0048] The optimization problem or objective can be one or more of the position and velocity described by the reference stroke curve information 200. The optimization problem can be solved online or offline. In online solving, the controller 150 is configured to calculate control parameters describing the optimized control strategy and execute model-based control using the calculated control parameters. In offline solving, the controller has an interface with a set of pre-calculated control parameters describing the optimized control strategy, and the controller is configured to execute model-based control using the pre-calculated control parameters. Furthermore, a hybrid approach is possible, where the controller calculates a finite set of control parameters for a certain selection quantity while using pre-calculated control parameters for other quantities.

[0049] exist Figure 2 In the block diagram, model 155 is an example of an engine circuit breaker (GCB) model, which receives model update parameters from the GCB model refresh module 170. The GCB model can be simplified to a controller 150 that can process control actions through calculation. Model 155 can be input into a reference stroke curve optimization module or directly added to the controller 150.

[0050] like Figure 2 As shown, controller 150 can be configured to select an appropriate control strategy. Alternatively, controller 150 can fix a control strategy. The control strategy includes at least one of the following: for example, using pre-computed control parameters through fast feedforward control and robust feedback control, and calculating control parameters and performing model-based control using the calculated control parameters, i.e., online control strategy optimization. Figure 2 In this paper, a model-based forward feedback strategy 151 is used to illustrate the use of pre-computed control parameters. Furthermore, in... Figure 2 In the example, Model Predictive Control (MPC152) demonstrates the calculation of control parameters and the execution of model-based control using these calculated parameters. During the execution of the selected control strategy, controller 150 generates actuator information 210.

[0051] For example Figure 2 As shown, the controller 150 outputs the generated actuator information 210 to the motor drive system 120, and indirectly to the circuit breaker forming the mechanical body 160 via the linkage device 140. Figure 2In this model, mechanical component 160 is designated "GCB / MD," which stands for Generator Circuit Breaker and Motor Drive System. Measured values ​​are fed back to controller 150 as control measurement feedback. Furthermore, operational data is output to model refresh module 170. Model refresh module 170 can output updated model data to adapt to model 155. The updated model data can reflect changes in the system, such as aging of the circuit breaker due to its lifespan or lifetime.

[0052] For example Figure 2 As shown, the model data output from model 155 can be input into the reference stroke curve optimization module 180. In the reference stroke curve optimization module 180, the reference stroke curve information 200 undergoes optimization for operational needs, such as motor constraints like torque and speed.

[0053] Figure 3 The desired stroke curve shown can be used as an exemplary basis for obtaining reference stroke curve information 200. For example, the desired stroke curve can be sampled and input into a controller or computer to obtain actual reference stroke curve information 200 suitable for controller 150.

[0054] like Figure 3 As shown, the stroke curve describes the movement between the starting position and the ending position. The starting position can be the closed position of the circuit breaker contacts, and the ending position can be its open position. However, the starting position can also be considered as the open position of the circuit breaker contacts, and the ending position can be its closed position.

[0055] exist Figure 3 In the diagram, the stroke curve describes the acceleration of the circuit breaker contacts as controlled by the controller and motor drive system 120, and also describes the deceleration phase. Therefore, acceleration and deceleration can transition smoothly, effectively improving the lifespan of the circuit breaker 110.

[0056] While the invention has been described above in exemplary embodiments, any aspect, feature, element, etc., and combinations thereof are illustrative. Those skilled in the art will devise many variations of the above-described techniques without departing from the spirit of the invention, the scope of which is defined in the following claims.

Claims

1. A circuit breaker device (100), comprising: Circuit breaker (110), which can be electrically connected to power line (115); A motor drive system (120) is mechanically coupled to the circuit breaker (110) and configured to operate the circuit breaker (110) to cause the circuit breaker (110) to perform a movement, the movement including at least a disconnection movement from a closed position to an open position, thereby electrically interrupting the power line (115); A controller (150) configured to control the motor drive system (120) based on a model (155) of at least one of the motor drive system (120) and the circuit breaker (110). The controller (150) is configured as follows: Receive reference stroke curve information (200) of the movement of the circuit breaker (110); Actuator information (210) is generated from the reference stroke curve information (200) based on the model (155); and The actuator information (210) is output to the motor drive system (120) to control the stroke curve of the circuit breaker (110) through model-based control.

2. The circuit breaker (100) as described in claim 1, wherein, The movement also includes a closing movement from the open position to the closed position.

3. The circuit breaker (100) as described in claim 1 or 2, wherein, The reference travel curve information (200) includes the time-dependent progress of a reference position of a portion of the motor drive system or the circuit breaker.

4. The circuit breaker (100) as described in claim 1 or 2, in, The motor drive system (120) includes a motor (130) connected to a linkage device (140), the linkage device (140) being configured to convert the rotational motion of the motor (130) into a substantially linear motion and output the linear motion to the circuit breaker (110); and The model (155) includes information about the motor torque between the motor (130) and the linkage device (140), and information about the reaction force between the linkage device (140) and the circuit breaker (110).

5. The circuit breaker (100) as claimed in claim 1, wherein, The model-based control includes employing an optimization control strategy to mathematically optimize at least one optimization objective in the optimization problem. The optimization objective is selected from the group consisting of the position described by the reference travel curve information (200) and the velocity described by the reference travel curve information (200).

6. The circuit breaker (100) as described in claim 5, in, The controller (150) has an interface for a set of pre-calculated control parameters describing the optimized control strategy; and The controller (150) is further configured to perform the model-based control using the pre-calculated control parameters via fast feedforward control and robust feedback control.

7. The circuit breaker (100) as claimed in claim 5, wherein, The controller is also configured to calculate and update control parameters describing the optimized control strategy, and to execute the model-based control as model predictive control using the calculated control parameters.

8. The circuit breaker device (100) as described in any one of claims 5 to 7, wherein, The optimization problem includes a cost function containing the optimization objective and at least one constraint equation, which describes a threshold of the magnitude of change of the circuit breaker during operation.

9. The circuit breaker (100) as claimed in claim 8, wherein, The threshold for the magnitude of the change includes one or more of the following: the separation speed of the circuit breaker contacts when the movement is an opening movement, the approach speed of the circuit breaker contacts when the movement is a closing movement, the temperature inside the circuit breaker chamber, the motor torque, and the linkage force.

10. The circuit breaker (100) as claimed in claim 1, wherein, The controller (150) is also configured to receive operational data related to the model parameters of the model, and to update the model parameters of the model using the received operational data.

11. The circuit breaker (100) as claimed in claim 1, wherein, The circuit breaker (110) is a generator circuit breaker used in power plants for generators.

12. The circuit breaker (100) as claimed in claim 11, wherein, The circuit breaker (110) is a generator circuit breaker with a rated current of 63kA or greater.

Images