Circuit breaker system

Abstract

For a circuit breaker system (3) including a first circuit breaker (1) and a second circuit breaker (2), the first circuit breaker (1) has a first trip unit, a first control unit and a first electrical sensor, the first control unit controls the first trip unit, the second circuit breaker (2) has a second trip unit, a second control unit and a second electrical sensor, the second control unit controls the second trip unit, the circuit breaker system (3) further includes means for communication between the first control unit and the second control unit, it is suggested that the first control unit monitors for the presence of an internal device fault in the second circuit breaker (2) via the means for communication, wherein the first control unit is adapted to change its standard trip characteristics to emergency trip characteristics when an internal device fault of the second circuit breaker (2) is detected.

Description

Technical Field

[0001] The present invention relates to a circuit breaker system according to the general part of claim 1. Background Technology

[0002] As a convention, programmable circuit breakers with processors and different tripping curves are used in different circuit breaker systems. A common practice is for distribution networks to include circuit breakers located downstream of other circuit breakers.

[0003] In the case of a faulty circuit breaker such as a miniature circuit breaker (MCB), hybrid circuit breaker (HCB), or solid-state circuit breaker (SSCB), different methods can be used to notify the system operator, such as immediate tripping or fault communication. However, due to this single fault, a part of the system may be offline or the safety level may be reduced. Tripping may also become impossible. In the case of a second fault, such as overcurrent or residual current, the fault level required to trip the upstream circuit breaker is higher than the original fault level.

[0004] For example, if the MCB detects a tripping condition but cannot fully perform the tripping due to an internal fault condition detected along the line after tripping has been initiated, parts of the system may be damaged while the devices are still trying to use them to interrupt the current. Such internal damage may occur, for example, if the interrupting semiconductor is unable to interrupt the tripping and the series isolating relay does not have the breaking capacity rating for this tripping current found in solid-state or hybrid circuit breakers. Other system components may also be damaged. For example, downstream lines may overheat due to higher currents because the upstream circuit breaker only trips after reaching its tripping threshold. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a circuit breaker system for achieving safe operation.

[0006] According to the present invention, the aforementioned objective is achieved by the features of claim 1.

[0007] As a result, the circuit breaker system achieves this objective and offers the advantage of safe operation. The first control unit monitors the second circuit breaker for internal component faults via a communication device. The first control unit is adapted to change the standard tripping characteristic of the second circuit breaker to an emergency tripping characteristic when an internal component fault is detected. This enables effective and rapid detection of internal component faults and avoids complete system failure. It also prevents defective circuit breakers from harmfully exploding and damaging surrounding components in the closure. Therefore, the safety level of the circuit breaker system is not reduced, and the overall system uptime is extended.

[0008] Another object of the present invention is to overcome the disadvantages of the prior art by providing a method for operating a circuit breaker system for achieving safe operation.

[0009] According to the present invention, the objective is achieved by the features of claim 8.

[0010] The advantages of this method are consistent with the advantages of the device.

[0011] The dependent claims describe other preferred embodiments of the invention. Attached Figure Description

[0012] The present invention is described with reference to the accompanying drawings. The drawings only show exemplary embodiments of the invention.

[0013] Figure 1 A preferred embodiment of the circuit breaker system is shown in the schematic diagram. Detailed Implementation

[0014] Figure 1 At least a portion of a preferred embodiment of a circuit breaker system 3 is shown, the circuit breaker system including a first circuit breaker 1 and a second circuit breaker 2, the first circuit breaker 1 having a first trip unit, a first control unit and a first electrical sensor, the first control unit controlling the first trip unit, the second circuit breaker 2 having a second trip unit, a second control unit and a second electrical sensor, the second control unit controlling the second trip unit, the circuit breaker system 3 further including means for communication between the first control unit and the second control unit, wherein the first control unit monitors for the presence of an internal component fault in the second circuit breaker 2 via the means for communication, wherein the first control unit is adapted to change its standard trip characteristics to emergency trip characteristics when an internal component fault of the second circuit breaker 2 is detected.

[0015] Furthermore, a method for operating a circuit breaker system 3 is provided, the circuit breaker system 3 including a first circuit breaker 1 and a second circuit breaker 2, the first circuit breaker 1 having a first tripping unit, a first control unit and a first electrical sensor, the first control unit controlling the first tripping unit, the second circuit breaker 2 having a second tripping unit, a second control unit and a second electrical sensor, the second control unit controlling the second tripping unit, wherein the first control unit communicates with the second control unit, wherein the first control unit monitors whether there is an internal component failure in the second circuit breaker 2, wherein when an internal component failure of the second circuit breaker 2 is detected, the first control unit changes its standard tripping characteristic to an emergency tripping characteristic.

[0016] In addition, a distribution network including circuit breaker system 3 is provided, wherein the first circuit breaker is located upstream of the second circuit breaker 2.

[0017] As a result, circuit breaker system 3 achieves this objective and has the advantage of enabling safe operation. The first control unit monitors for internal component failures in the second circuit breaker 2 via a communication device, wherein the first control unit is adapted to change the standard tripping characteristic of the second circuit breaker 2 to an emergency tripping characteristic when an internal component failure is detected. Internal component failures can be detected effectively and quickly, and complete system failure can be avoided. The defective circuit breaker 2 can be prevented from harmfully exploding and damaging surrounding components in the closure. Therefore, the safety level of circuit breaker system 3 is not reduced, and the overall system uptime is extended.

[0018] Circuit breaker system 3 is a system comprising at least two circuit breakers 1 and 2. A trip unit is part of circuit breakers 1 and 2, which disconnects the circuit in the event of thermal overload, short circuit, ground fault, or other causes. The trip unit can be an electromechanical or electronic trip unit. A first control unit controls the first trip unit, while a second control unit controls the second trip unit. The sensor can be a thermal sensor or an electrical sensor.

[0019] The circuit breaker system 3 includes means for communication between the first control unit and the second control unit. This means may be a communication protocol (Modbus RTU), fieldbus, wireless communication, or hardwired communication. This allows the trip enable signal to be connected to the trip electronics.

[0020] The first control unit monitors the second circuit breaker 2 for internal component failure via the communication device. Furthermore, the first control unit is adapted to change the standard tripping characteristics of the second circuit breaker 2 to emergency tripping characteristics when an internal component failure is detected.

[0021] Internal component failures, especially internal circuit breaker failures, are particularly likely to occur. These include failures or damage to the second control unit, potential switch failures, potential microcontroller failures, potential sensor failures, or excessively high temperatures in one or more components that prevent safe operation of the circuit breaker.

[0022] Typically, circuit breakers 1 and 2 are automatically operated electrical devices designed to protect circuits from damage caused by overcurrents from overloads or short circuits.

[0023] This invention can be implemented in all common circuit breaker systems. Therefore, in the following description, the terms circuit breaker 1, 2 can be collectively referred to as miniature circuit breaker (MCB), hybrid circuit breaker (HCB), solid-state circuit breaker (SSCB), residual current device (RCD), or residual current operated circuit breaker with overcurrent protection (RCBO) or arc fault detection device (AFDD). The residual current device can be a residual current circuit breaker (RCCB).

[0024] Specifically, the first control unit includes at least two predefined tripping characteristics. These tripping characteristics are stored in the first control unit. The first control unit always uses one of these tripping characteristics, wherein one of the tripping characteristics is a standard tripping characteristic used in the absence of internal device failure. The other tripping characteristic is an emergency tripping characteristic used in place of the standard tripping characteristic in the event of an internal device failure.

[0025] Preferably, the first control unit further includes an emergency tripping characteristic for the third circuit breaker, which exhibits a different tripping characteristic than the second circuit breaker 2. The third circuit breaker may have a different current rating than the second circuit breaker 2.

[0026] According to a preferred embodiment, the second control unit has means for detecting internal device faults in the second circuit breaker 2, and if the second control unit detects an internal device fault, the second control unit transmits the internal device fault of the second circuit breaker 2 to the first control unit. Preferably, the first control unit is adapted to change its standard tripping characteristics to emergency tripping characteristics when an internal fault of the second circuit breaker 2 is transmitted.

[0027] Preferably, the internal device fault is transmitted only when the device itself is faulty or malfunctioning and the fault could occur anywhere within circuit breaker 2. Furthermore, the internal device fault is preferably a downstream internal device fault in the second circuit breaker 2.

[0028] The first circuit breaker 1 and the second circuit breaker 2 may preferably include one or more microcomputers.

[0029] The first circuit breaker 1 and the second circuit breaker 2 can preferably be remotely programmable circuit breakers 1 and 2.

[0030] According to another preferred embodiment, the first control unit is adapted to continuously poll the second circuit breaker 2 to detect internal device failures in the second circuit breaker 2. Such a system can be referred to as a watchdog system. Preferably, the first circuit breaker 1 sends a signal that is responded to by the second circuit breaker 2, and if the second circuit breaker 2 does not respond to the signal, then a failure of the second circuit breaker 2, or more precisely, an internal device failure, is identified by the first circuit breaker 1.

[0031] Preferably, if an internal component failure of the second circuit breaker 2 is detected by the second control unit or the first control unit, the second circuit breaker 2 will not trip. Preferably, the second circuit breaker 2 enters an emergency mode where its tripping unit is disabled. By doing so, the defective second circuit breaker 2 is prevented from harmfully exploding and damaging its surrounding components.

[0032] According to another preferred embodiment, the second circuit breaker 2 has at least a semiconductor power switch. Preferably, at least one semiconductor switch is monitored for malfunction, particularly internal component failure, by a first control unit and / or a second control unit.

[0033] According to another preferred embodiment, the standard tripping characteristics and emergency tripping characteristics include a tripping current related to an overcurrent or short-circuit current threshold and / or a residual current threshold. The tripping current and / or residual current threshold are preferably predefined.

[0034] According to another preferred embodiment, the emergency tripping characteristics of the first control unit specifically comply with the tripping characteristics of the second control unit. Therefore, the tripping characteristics can be delegated in an easy manner.

[0035] As previously described, a distribution network including a circuit breaker system 3 is provided, wherein a first circuit breaker is located upstream of a second circuit breaker 2. The distribution network has at least one power line 4, which is monitored in series by the first circuit breaker 1 and the second circuit breaker 2. Therefore, the first circuit breaker 1 is preferably an upstream circuit breaker and the second circuit breaker 2 is preferably a downstream circuit breaker. The upstream circuit breaker is closer to the power plant, and the downstream circuit breaker is closer to the consumer. The upstream circuit breaker typically has a higher current rating and tripping time to achieve selectivity at the downstream level.

[0036] refer to Figure 1 In the preferred embodiment shown, the first circuit breaker 1 is connected to a plurality of second circuit breakers 2. The power line 4 may include branches.

[0037] Furthermore, to increase the opportunity for user-initiated fault detection, preferably, when an internal component fault is detected, the first control unit or the second control unit outputs a fault message to notify the user of the fault. The fault message can be a text message displayed on the screen, or it can be output via an optical device such as a flash.

[0038] As mentioned earlier, in Figure 1 An exemplary embodiment of a preferred circuit breaker system 3 is shown. It includes a first circuit breaker 1, and in particular an upstream circuit breaker connected to a plurality of second circuit breakers 2, particularly downstream circuit breakers. Such a system having downstream and upstream circuit breakers is generally referred to as a layered circuit breaker system or structure.

[0039] For example, if the control unit of the first circuit breaker 1 detects an internal device failure in one of the second circuit breakers 2, the first control unit changes its standard tripping characteristic to an emergency tripping characteristic.

[0040] In a preferred embodiment, tripping can be delegated from the second circuit breaker 2 to the first circuit breaker 1, and thus from the downstream circuit breaker to the upstream circuit breaker. This delegation can be achieved using a hardwired connection directly to the upstream tripping mechanism or using some advanced communication interface such as fieldbus or wireless communication.

[0041] Alternatively, if the second circuit breaker 2, particularly the downstream circuit breaker, detects an internal component failure before an additional system failure occurs, it preferably delegates its tripping characteristics to the first circuit breaker 1, particularly the upstream circuit breaker. For example, if the downstream circuit breaker has a tripping threshold of 16A and the upstream circuit breaker has a tripping threshold of 40A, the upstream circuit breaker can take over the 16A tripping threshold and replace the downstream circuit breaker. Furthermore, it is preferable to notify the system operator and ensure a safe and normally functioning system.

[0042] According to another preferred embodiment, the safety level of the circuit breaker system 3 can be further enhanced by additionally implementing a life-saving system. Preferably, the first circuit breaker 1 periodically polls the status of at least one second circuit breaker 2. If a second circuit breaker 2 does not respond, the first circuit breaker 1 preferably enters an emergency mode and takes over the tripping characteristics of the unresponsive second circuit breaker 2 according to a predefined emergency plan or general emergency characteristics.

[0043] Alternative implementations can preferably use emergency messages automatically sent from at least one second circuit breaker 2, particularly downstream devices. If the first circuit breaker 1, particularly the upstream circuit breaker, does not receive the message from at least one of its second circuit breakers 2 within a predefined number of times, it can also enter the aforementioned emergency mode.

[0044] Preferably, the circuit breaker system 3 and thus the distribution network includes at least one, preferably multiple, first circuit breakers 1 and multiple second circuit breakers 2.

[0045] While the invention has been specifically shown and described with reference to exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The exemplary embodiments should be considered descriptive only and not for limiting purposes. Therefore, the scope of the invention is defined not by the detailed description but by the appended claims.

[0046] The principles used below to understand and explain the actual public content are explained.

[0047] Features are usually described using the indefinite articles "a kind of," "one," or "an." Unless otherwise stated in the context, "a kind of," "one," or "an" should not be understood as a numeral.

[0048] Unless the context otherwise specifies, the conjunction "or" must be interpreted as inclusive rather than exclusive. "A or B" also includes "A and B", where "A" and "B" represent random features.

[0049] Unless otherwise specified in the disclosure of this invention, in several embodiments, particular feature X or object Y is distinguished by ordering numerals such as "first," "second," or "third." Specifically, the presence of ordering numerals for feature X or object Y in the claims does not imply that the embodiments of the invention covered by these claims must have another feature X or another object Y.

Claims

1. A circuit breaker system (3), the circuit breaker system (3) comprising: A first circuit breaker (1) and a second circuit breaker (2), wherein the first circuit breaker (1) has a first tripping unit, a first control unit and a first electrical sensor, the first control unit controls the first tripping unit, and the second circuit breaker (2) has a second tripping unit, a second control unit and a second electrical sensor, the second control unit controls the second tripping unit, wherein the circuit breaker system (3) further includes a means for communication between the first control unit and the second control unit, the first control unit monitoring for internal device faults in the second circuit breaker (2) via the means for communication, wherein the first control unit is adapted to change its standard tripping characteristics to emergency tripping characteristics when an internal device fault of the second circuit breaker (2) is detected.

2. The circuit breaker system (3) according to claim 1, characterized in that, The second control unit has means for detecting internal device faults in the second circuit breaker (2), and if the second control unit is detecting an internal device fault, the second control unit sends the internal device fault of the second circuit breaker (2) to the first control unit.

3. The circuit breaker system (3) according to claim 1 or 2, characterized in that, The first control unit is adapted to continuously poll the second circuit breaker (2) to detect internal device faults in the second circuit breaker (2).

4. The circuit breaker system (3) according to any one of claims 1 to 3, characterized in that, The second circuit breaker (2) has at least a semiconductor switch.

5. The circuit breaker system (3) according to any one of claims 1 to 4, characterized in that, The standard tripping characteristics and the emergency tripping characteristics include tripping currents related to overcurrent or short-circuit current thresholds and / or residual current thresholds.

6. The circuit breaker system (3) according to any one of claims 1 to 5, characterized in that, The emergency tripping characteristics of the first control unit specifically comply with the tripping characteristics of the second control unit.

7. A power distribution network comprising a circuit breaker system (3) according to any one of claims 1 to 6, wherein the first circuit breaker is located upstream of the second circuit breaker (2).

8. A method for operating a circuit breaker system (3), the circuit breaker system (3) comprising: A first circuit breaker (1) and a second circuit breaker (2), wherein the first circuit breaker (1) has a first tripping unit, a first control unit and a first electrical sensor, the first control unit controls the first tripping unit, and the second circuit breaker (2) has a second tripping unit, a second control unit and a second electrical sensor, the second control unit controls the second tripping unit, wherein the first control unit communicates with the second control unit, the first control unit monitors whether there is an internal device fault in the second circuit breaker (2), wherein when an internal device fault is detected in the second circuit breaker (2), the first control unit changes its standard tripping characteristic to an emergency tripping characteristic.

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