REDUNDANT RELAY SYSTEMS AND RELATED METHODS FOR USE WITH SWITCHGEAR

Methods and systems for redundant relay systems for use with switchgears. One example system includes a switch module including a switching device therein, a coil circuit operatively coupled to the switch module to control a position of the switching device, a switchgear relay circuit, and a back-up trip circuit. The back-up trip circuit includes a polarity control device, a changeover device, and an electronic processor. The electronic processor is configured to monitor for a loss of power to the switchgear relay circuit or for a switchgear relay failure, and in response to detecting either of the loss of power or the switchgear relay failure, operate the switch module by actuating the changeover device to disconnect the coil circuit from the switchgear relay circuit and connect the coil circuit to the polarity control device of the back-up trip circuit.

BACKGROUND OF THE INVENTION

Distributed energy resources (DERs) refer to renewable energy generation units/systems (for example, solar arrays, wind turbines, etc.) located on a consumer side (a business or a home) of an electrical power distribution system (e.g., an electrical grid) to provide a business or home with power. DERs are also referred to as “behind the meter” because the electricity of such systems is generated and managed “behind” the electricity meter in the consumer facility.

The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments, examples, aspects, and features so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

DETAILED DESCRIPTION OF THE INVENTION

Electrical power distribution systems include fault monitoring equipment that identifies problems in the system and opens isolation devices to isolate the problems. Example problems with the electrical power distribution systems include overcurrent faults, phase-to-phase faults, ground faults, and others. These problems may arise from various causes, such as equipment failure, weather-related damage to equipment, etc. Switching equipment (for example, recloser relay systems) is provided in electrical power distribution system to isolate the detected faults.

As noted above, DERs interconnected to electrical grids may be utilized by consumers at a home or at a business. Such systems may be required to comply with certain professional industry standards (for example, those issued by the Institute of Electrical and Electronics Engineers (IEEE)). Some such standards may include what actions are to be performed with respect to a DER in case of certain faults or other events within the system. For example, IEEE 1547 requires that isolation devices of DER interconnections operate (trip) in the event of a loss of power/potential in the grid, thereby disconnecting the DER from the electrical grid. While some DER systems may utilize one or more recloser relay circuits to disconnect the DERs, such recloser relay circuits may fail to operate in certain instances (for example, due to a software and/or hardware failure or a loss of power (“LOP”) to the recloser relay circuit itself). In such instances, there is no ability to meet the IEEE 1547 requirement.

These and other related problems in the field can be beneficially addressed using at least some embodiments, examples, aspects, and features disclosed herein. Various examples provide, among other things, a back-up redundant relay system that monitors for certain electrical events associated with the recloser relay circuit (e.g., a failure of the recloser relay circuit to operate) when a DER interconnection is required to be tripped and performs one or more actions to disconnect and isolate the DER from an electrical grid source absent functioning the recloser relay circuit. In some instances, the back-up redundant relay system disclosed herein is provided with a trip circuit, separate from the recloser relay circuit, that can be advantageously utilized in a switchgear system to provide redundant control functionality to the switchgear with respect to the tripping operation. This redundancy helps improves safety and reliability of the switchgear.

One example provides a switchgear system including a switch module including a switching device therein, a coil circuit operatively coupled to the switch module to control a position of the switching device, a switchgear relay circuit, and a back-up trip circuit. The back-up trip circuit includes a polarity control device, a changeover device, and an electronic processor. The electronic processor is configured to monitor for a loss of power to the switchgear relay circuit or for a switchgear relay failure, and in response to detecting either of the loss of power or the switchgear relay failure, operate the switch module by actuating the changeover device to disconnect the coil circuit from the switchgear relay circuit and connect the coil circuit to the polarity control device of the back-up trip circuit.

Another example provides a back-up trip circuit for a switchgear relay circuit of a switchgear system. The circuit includes a polarity control device, a changeover device, and an electronic processor. The electronic processor is configured to monitor for a loss of power to the switchgear relay circuit or for a switchgear relay failure, and in response to detecting either of the loss of power or the switchgear relay failure, operate a switch module by actuating the changeover device to disconnect a coil circuit operatively coupled to the switch module to control a position of a switching device therein from the switchgear relay circuit and connect the coil circuit to the polarity control device of the back-up trip circuit.

Another example provides a method for operating a back-up trip circuit for a switchgear relay circuit of a switchgear system, the back-up trip circuit including a polarity control device and a changeover device. The method includes monitoring for a loss of power to the switchgear relay circuit or for a switchgear relay failure, and in response to detecting either of the loss of power or the switchgear relay failure, operating a switch module by actuating the changeover device to disconnect a coil circuit operatively coupled to the switch module to control a position of a switching device therein from the switchgear relay circuit and connect the coil circuit to the polarity control device of the back-up trip circuit.

Yet another example provides a non-transitory, computer-readable medium, comprising commands which, when executed by a computer, cause the computer to control a back-up trip circuit for a switchgear relay circuit of a switchgear system, the back-up trip circuit including a polarity control device and a changeover device, by monitoring for a loss of power to the switchgear relay circuit or for a switchgear relay failure, and in response to detecting either of the loss of power or the switchgear relay failure, operating a switch module by actuating the changeover device to disconnect a coil circuit operatively coupled to the switch module to control a position of a switching device therein from the switchgear relay circuit and connect the coil circuit to the polarity control device of the back-up trip circuit.

For ease of description, some or all of the examples, aspects, and features presented herein are illustrated with a single exemplar of each of its component parts. Some examples may not describe or illustrate all components of the systems. Other examples may include more or fewer of each of the illustrated components, may combine some components, or may include additional or alternative components. It should also be understood that although the examples described herein are in terms of being utilized for DER interconnections, it should be understood that the systems and methods described herein may be applied to other configurations of electrical power distribution system interconnections.

Unless the context of their usage unambiguously indicates otherwise, the articles “a,” “an,” and “the” should not be interpreted as meaning “one” or “only one.” Rather these articles should be interpreted as meaning “at least one” or “one or more.” Likewise, when the terms “the” or “said” are used to refer to a noun previously introduced by the indefinite article “a” or “an,” “the” and “said” mean “at least one” or “one or more” unless the usage unambiguously indicates otherwise.

It should also be understood that although certain drawings illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. In some embodiments, the illustrated components may be combined or divided into separate software, firmware and/or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links.

Thus, in the claims, if an apparatus or system is claimed, for example, as including an electronic processor or other element configured in a certain manner, for example, to make multiple determinations, the claim or claim element should be interpreted as meaning one or more electronic processors (or other element) where any one of the one or more electronic processors (or other element) is configured as claimed, for example, to make some or all of the multiple determinations. To reiterate, those electronic processors and processing may be distributed.

FIG.1Ais a simplified diagram of an electrical power distribution system10in accordance with some examples. In the example illustrated, the electrical power distribution system10includes an electrical grid source15and a client source20(for example, a DER system). The electrical power distribution system10further includes a switchgear system100disposed between the electrical grid source15and the client source20. As explained in more detail below, the switchgear system100is configured to disconnect (e.g., temporarily disconnect) the client source20from the electrical power distribution system10(and any other devices upstream of the switchgear system100), for example, in instances of a fault such as LOP faults, overcurrent faults, phase-to-phase faults, ground faults, etc. To facilitate breaking, interrupting, and/or, more generally, terminating a flow of electric current between the grid source15and the client source20, the switchgear system100is provided with one or more switchgear (for example, the switchgear120illustrated inFIG.1C) electrically connected to the grid source15and the client source20.

In some examples, the switchgear system100forms and/or defines at least part of a DER system. In such examples, the client source20ofFIG.1Acan be provided with one or more energy resources25electrically connected to the switchgear system100, for example, directly to the switchgear and/or via one or more intermediate elements (e.g., a breaker) of the DER system interposed between the switchgear and the resource(s)25. In the illustrated example ofFIG.1A, the energy resource(s)25include any of, for example, one or more photovoltaic (PV) panels (e.g., a PV array), one or more wind turbines, one or more batteries, and the like, or a combination thereof.

FIG.1Bis a block diagram of the switchgear system100for the electrical power distribution system10in accordance with some examples. In this example, to facilitate operating the switchgear, the system100includes a switchgear relay circuit102and a back-up trip circuit104separate from and/or external to the switchgear relay circuit102. The switchgear relay circuit102includes a trip circuit105, a first electronic controller106, and a first energy management system107. The trip circuit105of the switchgear relay circuit102is sometimes referred to as a primary trip circuit, while the back-up trip circuit104is sometimes referred to as a secondary or redundant trip circuit. The back-up trip circuit104includes a changeover device108(for example, a Form C circuit or similar circuit), a polarity control device110(for example, an h-bridge circuit or a similar circuit), and a second electronic controller200(which is illustrated and described in more detail below in regard toFIG.2). Additionally, in some examples, to allow for independent power functions, the back-up trip circuit104is provided with a second energy management system111distinct from the first energy management system107of the switchgear relay circuit102. The back-up trip circuit104is operationally interposed between the switchgear relay circuit102and a coil circuit112of the switchgear system100.

To help facilitate efficient and reliable circuit operation, the first energy management system107is provided with one or more devices configured to perform power-related functions within the switchgear relay circuit102. For example, the first energy management system107may include a first power supply (not shown) configured to convert electrical power (e.g., from an alternating current (AC) to a direct current (DC) for use by the switchgear relay circuit102and, in some examples, for use by the back-up trip circuit104. Additionally or alternatively, the first power supply regulates and/or filters voltage to ensure stable and/or clean power is supplied to the circuit102. Additionally, in some examples, the first energy management system107is provided with a first energy storage device (for example, one or more capacitors), which is not shown, configured to store electrical energy (for example, energy supplied by the first power supply). Such stored electrical energy may be released by one of the (a) trip circuit105or (b) the back-up trip circuit104in an advantageous and/or controlled manner to drive switchgear operation.

Additionally or alternatively, in some examples, the back-up trip circuit104includes the second energy management system111. The second energy management system111may be configured the same or similar relative to the first energy management system107. In one example, the second energy management system111includes similar components and performs at least some or all of the functions of the first energy management system107. Accordingly, the second energy management system111may serve as a redundant system capable of suitably powering the back-up trip circuit104, or at least part thereof, to enable switchgear operation (for example, if the first energy management system107malfunctions or ceases to provide electrical power to the back-up trip circuit104). In some examples, the second energy management system111or a device thereof (e.g., a second power supply) receives electrical power from an alternating current (AC) source113that is external to the switchgear relay circuit102, which creates additional redundancy in the system.

In some examples, the switchgear relay circuit102can be implemented using an advanced recloser control. In such examples, as explained in more detail below, the switchgear relay circuit102can function as a recloser (also known as an autorecloser) by interacting with one or more current and/or voltage sensors associated with the switchgear100(shown and described in more detail below in regard toFIG.2) and protection relays (not shown) configured to open (“trip”) the interconnection between the sources15and20. As also explained in more detail below, the back-up trip circuit104is configured to monitor for certain electrical events during which action is to be taken and/or for conditions of the switchgear relay circuit102indicative of such events. In one example, the back-up trip circuit104monitors for a LOP of the switchgear relay circuit102and/or for a failure of the switchgear relay circuit102.

In monitoring for a LOP, the electronic controller200may utilize readings from one or more voltage or current sensors (sensors235ofFIG.2) or a suitable monitoring circuit (not shown) within or outside of the switchgear relay circuit102to detect instances where the switchgear relay circuit102no longer receives power from the respective first energy management system107or otherwise is unable to function properly. The back-up trip circuit104or at least a component thereof is configured to change state when an LOP is detected, thereby changing electrical connections between the coil circuit112, the switchgear relay circuit102, and the back-up trip circuit104. For example, in response to the electronic controller200transmitting one or more signal(s) and/or command(s) to the changeover device108, the back-up trip circuit104changes from a first circuit state providing primary electrical pathways in the switchgear system100to a second circuit state providing one or more different or secondary electrical pathways in the switchgear system100.

In some examples, when in the first circuit state, the changeover device108forms, defines, and/or maintains a first electrical connection between the coil circuit112and the switchgear relay circuit102, while keeping the coil circuit112electrically disconnected from the polarity control device110. In this manner, the switchgear relay circuit102is enabled to control the coil circuit112to operate the associated switchgear. On the other hand, when in the second circuit state, the changeover device108forms, defines, and/or maintains a second electrical connection between the coil circuit112and the polarity control device110, while electrically disconnecting the coil circuit112from the switchgear relay circuit102and/or keeping the coil circuit112electrically disconnected therefrom. In this manner, the polarity control device110is enabled to control the coil circuit112to operate the associated switchgear (instead of the switchgear relay circuit102), and the switchgear relay circuit102is disabled or prevented from controlling the coil circuit112. Such a circuit state change allows for transfer of control of the coil circuit112from the switchgear relay circuit102to the back-up trip circuit104.

Each coil of the coil circuit112is associated with a respective electrical phase of the electrical power distribution system10. In the illustrated example, the system100is configured for a three-phase system and, thus, the coil circuit112includes three actuator coils114A-114C. In some examples, each coil114A-114C of the coil circuit112is a single magnetic actuator coil. In other examples, each coil114A-114C is implemented differently, for example, using a solenoid coil. Further, the polarity control device110comprises one or more devices for controlling circuit polarity, each corresponding to a respective phase (and coil thereof). The polarity control device110may include, for example, one or more h-bridges or h-bridge circuitry, one or more transistor arrays, other suitable circuitry or electronics operable to adjust, change, and/or maintain circuit polarity, or some combination thereof. In the illustrated example, the polarity control device110includes three h-bridges116A-116C each, as explained in more detail below, corresponding to a respective coil114A-114C of the coil circuit112. In some examples, the trip circuit105may be configured similar to that of the polarity control device110. For example, in the illustrated example, the trip circuit105also includes three h-bridges118A-118C, each corresponding to a respective coil114A-114C of the coil circuit112. In alternative embodiments, the main trip circuit105and/or the back-up trip circuit104is/are a different configuration than the h-bridge circuitry illustrated inFIG.1B. It should be understood that, although the switchgear system100is illustrated as being for a three-phase electric power distribution system (for example, the electrical power distribution system10), the system100may be configured for any number phase electric power distribution system.

Communications between the first and second electronic controllers106,200, in the illustrated example, are performed via one or more communication networks or links, including various wired and wireless networks and links (for example, a wide area network (such as, for example, the Internet), a local area network (such as, for example, a Wi-Fi network), a short-range wireless network or connection (for example, a Bluetooth network), or a combination of the same). In some embodiments, either or both of the electronic controllers106,200are configured to communicate with additional external systems, networks, or devices (for example, a separate electronic communications device such as a smart phone, a computer, etc.) using different respective communication links, which are not shown.

FIG.1Cis a view of example switchgear120for the system100in accordance with some aspects. The switchgear120ofFIG.1Ccan be used to the implement at least part of the switchgear system100previously described. In some examples, the switchgear120is a medium or high voltage solid-dielectric recloser having one or more electrical phases. In other examples, the switchgear120is a solid-dielectric fault interrupting switch having one or more electrical phases. Tripping operation of the switchgear120can be driven by means of actuator output and/or, in some instances, mechanical energy (e.g., spring energy) stored via one or more mechanisms of the switchgear120. In particular, the switchgear120is configured to electrically connect to part of the client source20(e.g., the energy resource(s)25) and the electrical grid source15, for example, via one or more cables, cable accessories, and the like, or a combination thereof.

According to the illustrated example ofFIG.1C, the switchgear120includes one or more modules (e.g., solid-dielectric switch modules), three of which are shown (i.e., a first module122A, a second module122B, and a third module122C). Each module122A-122C of the switchgear120is sometimes referred to as a switch module and can be implemented, for example, using at least a switching device (e.g., a vacuum bottle interrupter) and a body (e.g., a cured epoxy resin mixture) forming a protective and/or insulated housing around the switching device. Additionally, each module122A-122C can be provided with electrical terminals (e.g., any of IEEE compliant bushing interfaces, aerial lugs, bushing insulators, etc.) to facilitate creating electrical connections from cabling external to the switchgear120to a switching device internal to the module. In normal operation, the modules122A-122C can be independently operated or operated together (e.g., in a substantially synchronized manner).

For brevity,FIG.1Cand the accompanying description below depict aspects in connection with a single switch module122A of the switchgear120. However, in some examples, at least some or all such aspects likewise apply to one or more (e.g., all) other switch module(s)122B-122C of the switchgear120. In the illustrated example ofFIG.1C, the first module122A includes a switching device124(represented by the dotted/dashed lines ofFIG.1C) and a housing126in which the switching device124A is disposed. The switching device124ofFIG.1Ccan include a first portion (e.g., a fixed electrical contact) and a second portion (e.g., a movable electrical contact) movable relative to the first portion. In some examples, the switching device124is molded into the housing126, for example, using one or more molding methods and/or techniques associated with curing epoxy resin mixtures.

To facilitate rapid switching operation, the first module122A and/or, more generally, the switchgear120includes an actuator128(represented by dotted/dashed lines ofFIG.1C) operatively coupled to the switching device124. The actuator128can be disposed in or adjacent the housing126proximate to the switching device124. In one example, the actuator128ofFIG.1Cis configured to apply an actuator output to the switching device124, for example, via one or more intermediate linkages (e.g., a drive rod assembly) in the housing126connecting the actuator128to the switching device124. Such intermediate linkage(s) in the first switch module122A is/are structured to transfer output from a component of the actuator128to a component of the switching device124.

The actuator128ofFIG.1Ccan be implemented, for example, using a single coil magnetic actuator. In the illustrated example ofFIG.1C, the actuator128includes an actuator coil to control a position of the switching device124. Such a coil can include or correspond to one of the coil(s)114A-114C of the coil circuit112previously described. In one example, the actuator128is configured to generate, via the actuator coil, an output (e.g., a force) and/or applies the output to the switching device124, thereby changing the position of the switching device124(e.g., from a closed position to an open position) to terminate an electric current flowing through or across the switching device124.

Additionally, in some examples, the switchgear120includes a frame129supporting the switch module(s)122A-122C. In the illustrated example ofFIG.1C, the switch module(s)122A-122C are fixedly coupled to the frame129, for example, via one or more fasteners and/or fastening methods or techniques. Further, in such examples, the frame129can be provided with a first bracket (e.g., a pole mounting bracket) affixed thereto, which can facilitate mounting and/or securing the switchgear120at an elevated position. In such examples, the first bracket is configured to couple to a structure (e.g., a pole) capable of supporting the weight of the switchgear120such as, for example, a wood pole, a steel pole, a composite pole, etc. WhileFIG.1Cdepicts particular aspects of the switchgear120in connection certain with frame structures and mounting applications, it should be noted that the frame129, the first bracket, and/or, more generally, the switchgear120ofFIG.1Ccan be configured differently for use in different applications (e.g., padmount applications and/or vault applications).

WhileFIG.1Cdepicts certain aspects in connection with actuator-driven switchgear, it should be understood that the switchgear120of the system100may be implemented differently. For example, the switchgear120may be structured such that one or more (e.g., all) of the module(s)122A-122C is/are substantially mechanically driven. In such instances, with respect to the single switch module122A, the actuator128includes a solenoid (e.g., a manual reset latching solenoid) configured to operate or trigger a driving mechanism (not shown) of the switchgear120operatively coupled between the solenoid and the switching device124. Such a solenoid has a single polarity and can be activated via a relatively low energy input (compared to a single coil magnetic actuator) which, in turn, causes the driving mechanism to change the position of the switching device124via the stored mechanical energy. The driving mechanism may include, for example, a spring-driven mechanical mechanism having one or more spring elements configured to store spring energy and, in response to the actuator128engaging a certain lever or trigger portion of the driving mechanism, apply the spring energy to the switching device124(e.g., directly or via the intermediate linkage(s)) to change the switching device position.

FIGS.1D and1Eare views of an example enclosure (e.g., a junction box)130for the system100ofFIG.1Bin accordance with some aspects. The enclosure130can be advantageously utilized to house at least some electronics associated with the switchgear120and, in particular, create a substantially isolated environment in which the electronics can safely function.

The enclosure130includes a body132forming a cavity134(shown inFIG.1E) in which the electronics are disposed. The enclosure130can be provided with a cover portion136(shown inFIG.1D) positioned on the body132to cover an opening of the cavity134. The body132and the cover portion136, together, surround the internal electronics to create a physical barrier substantially blocking external elements or matter from entering the cavity134and/or interfering with the electronics. The cover portion136includes, for example, a plate, a door, and the like, or a combination thereof. In some examples, the cover portion136is pivotably coupled to the body132to allow for user access to the internal electronics, for example, via one or more hinges interposed between the body132and the cover portion136. Alternatively, in some examples, the cover portion136is removably coupled to body132, for example, via one or more removable fasteners and/or one or fastening methods or techniques.

In some examples, during switchgear installation, the enclosure130mounts to a structure in proximity to the switchgear120, which allows for personnel to electrically connect the internal electronics to the switch module(s)122A-122C (e.g., via wire routing). For example, the enclosure130can be configured to couple to part of the frame129. Alternatively, the enclosure130can be configured to couple to a different structure (e.g., a wall, a pole, pedestal, etc.) such that the enclosure130is positioned at a relatively short distance (e.g., 10 ft., 25 ft., 50 ft., etc.) from the switchgear120. In some examples, the enclosure130and the switchgear120are positioned on the same structure. In any case, the enclosure130can be provided with a second bracket (e.g., one of a frame-mounting bracket, a wall-mounting bracket, a pole-mounting bracket, etc.)138supporting the body132that is configured to affix the enclosure130to the structure, which is different from the first bracket of the switchgear120previously described.

Turning in detail toFIG.1E, the cover portion136has been removed from the enclosure130to show electronics and related components of interest therein. According to the illustrated example ofFIG.1E, the enclosure130is provided with a first circuit board140, a second circuit board142, and a capacitor bank144, each of which is disposed in the cavity134and coupled to the enclosure body132, for example, via one or more fasteners and/or fastening methods or techniques. In particular, one or more (e.g., all) of the first circuit board140, the second circuit board142, and/or the capacitor bank144can be used to implement the back-up trip circuit104or at least part thereof.

In some examples, the first circuit board140and the capacitor bank144, together, form the second energy management system111and/or perform at least some or all functions thereof. For example, the first circuit board140includes a power supply circuit, and the capacitor bank144includes one or more capacitors configured to store electrical energy supplied by the power supply circuit. As shown inFIG.1E, the capacitor bank144is provided with a first capacitor146A and a second capacitor146B that, together, are configured to store the electrical energy for switchgear operation. Further, the second circuit board142includes switchgear control circuitry that can be configured to operate the module(s)122A-122C of the switchgear120using electrical energy supplied by the first circuit board140and/or stored in the capacitor bank144.

FIG.2schematically illustrates one example of the electronic controller200of the back-up trip circuit104. In the example illustrated, the electronic controller200includes an electronic processor210, a memory220, and an input/output interface230. The electronic processor210, the memory220, and the input/output interface230communicate over one or more control and/or data buses.FIG.2illustrates only one example of an electronic controller200. The electronic controller200may include more or fewer components and may perform functions other than those explicitly described herein.

In some instances, the electronic processor210is implemented as a microprocessor with separate memory, such as the memory220. In other instances, the electronic processor210may be implemented as a microcontroller (with memory220on the same chip). In other instances, the electronic processor210may be implemented using multiple processors. In addition, the electronic processor210may be implemented partially or entirely as, for example, a field-programmable gate array (FPGA), and application specific integrated circuit (ASIC), and the like and the memory220may not be needed or be modified accordingly. In the example illustrated, the memory220includes non-transitory, computer-readable memory that stores instructions that are received and executed by the electronic processor210to carry out functionality of the system100described herein. The memory220may include, for example, a program storage area and a data storage area. The program storage area and the data storage area may include combinations of different types of memory, such as read-only memory and random-access memory.

The input/output interface230may be connected to one or more input mechanisms (for example, a touch screen, a keypad, a button, a knob, a microphone, sensors, and the like), one or more output mechanisms (for example, a display, one or more light-emitting diodes (LEDs), a speaker, etc.), or some combination thereof. The input/output interface230may also include one or more sensors (for example, sensors235). The sensors235include one or more voltage sensors and/or current sensors positioned (e.g., on the switchgear120and/or switch module(s)122A-122C) to monitor the one or more phases of the interconnection upstream and/or downstream and, in some embodiments, a power input to the switchgear relay circuit102and/or a power input to the back-up trip circuit104.

The input/output interface230receives input or signals from input devices, for example, actuated by a user, and provides output or signals to output devices. For example, as explained in more detail below, the electronic controller200is configured to operate the changeover device108and/or the polarity control device110based on one or more inputs indicating a LOP to or a hardware or software failure of the switchgear relay circuit102(either directly from a sensor, a monitoring circuit, the electronic controller106, and/or a separate electronic communications device). In some instances, as an alternative or in addition to managing inputs and outputs through the input/output interface230, the electronic controller200may receive input, provide output, or both by communicating with an external device, such as an electronic communications device, over a wired or wireless connection.

In some embodiments, the electronic controller200includes a transceiver240. The transceiver240enables wireless communication from the controller200to, for example, the electronic controller106and/or other devices of the system100. In other instances, rather than the transceiver240, the electronic controller200may include separate transmitting and receiving components, for example, a transmitter, and a receiver. In yet other instances, the electronic controller200may not include a transceiver240and may communicate with the components of the system100(for example, the electronic controller106, via a wired connection.

The electronic controller200is configured to receive power from an energy management system. In some embodiments, the electronic controller200receives power from the first energy management system107of the switchgear relay circuit102. In such embodiments, the electronic controller200further includes a back-up energy storage unit (for example, a battery, one or more capacitors, etc.), which is not shown, for use in instances where there is a LOP (as described below). Alternatively or additionally, the electronic controller200, in some embodiments, receives power from the second energy management system111of the back-up trip circuit104.

FIG.3schematically illustrates one example of the electronic controller106of the switchgear relay circuit102. In the example illustrated, the electronic controller106includes an electronic processor310, a memory320, and an input/output interface330. The electronic processor310, the memory320, and the input/output interface330communicate over one or more control and/or data buses.FIG.3illustrates only one example of an electronic controller106. The electronic controller106may include more or fewer components and may perform functions other than those explicitly described herein.

The electronic processor310, a memory320, and an input/output interface330including one or more sensors335and, in some embodiments, a transceiver340of the first electronic controller106are similar to the electronic processor210, the memory220, the input/output interface230, and the transceiver240of the second electronic controller200and, thus, for sake of brevity, are not discussed in detail herein. The sensors335of the first electronic controller106comprise one or more voltage and/or current sensors configured to measure one or more characteristics of the electrical connection(s) between the electrical grid source15and the client source20. The electronic processor310, in particular, utilizes the information from the sensors335to detect whether a fault has occurred within the system100and/or has been cleared.

Returning toFIG.1B, during normal operation, the switchgear relay circuit102is configured to monitor for a fault relative to (e.g., upstream or downstream from) the switchgear system100. In response to such a detected condition, the switchgear relay circuit102(in particular, the electronic controller106thereof) activates the trip circuit105(for example, each of the h-bridges118A-118C) to flip the polarity of each of the respective actuator coils114A-114C of the coil circuit112. This polarity adjustment of the coil circuit112opens the interconnection between the electrical grid source15and the client source20, effectively “tripping” the system100and disconnecting the client source20or the energy resource(s)25from the electrical grid source15.

As mentioned above, failure to isolate a fault within the electrical distribution system may cause damage, for example, further upstream the system10. Thus, in instances where the switchgear relay circuit102fails to open/trip, it is beneficial to have the secondary trip circuit104to perform the trip.

FIG.4illustrates an example method400for operating the back-up trip circuit104of the switchgear system100for the electrical power distribution system10in accordance with some examples. Although the method400is described in conjunction with the system100, the method400could be used with other systems and devices. In addition, the method400may be modified or performed differently than the specific example provided.

As noted, the method400is described as being performed by the electronic controller200and, in particular, the electronic processor210. However, it should be understood that in some instances, portions of the method400may be performed by other devices. For example, additional electronic processors, such as the electronic processor310, may be included in the system100that perform all or a portion of the method400. For ease of description, the method400is described in terms of a single switchgear relay circuit (for example, the switchgear relay circuit102). However, the method400may be applied to multiple switchgear relay circuits (for example, simultaneously).

At block401, the electronic processor210controls an energy management system to store electrical energy for switchgear operation. In some examples, the electronic processor210directs the first energy management system107, the second energy management system111, or combination thereof to store electrical energy in one or more energy storage devices (e.g., the capacitor bank144) of the switchgear system100.

At block402, the electronic processor210monitors for a loss of power to the switchgear relay circuit102(for example, according to readings from the sensor(s)235). In one example, the electronic processor210detects when a parameter of an electric current (e.g., a DC current) transmitted from the switchgear relay circuit102to the back-up trip circuit104drops below a target threshold (e.g., preprogrammed in the electronic controller200) indicative of normal operation. The target threshold can be a value corresponding to an output parameter (e.g., one of voltage, amperage, etc.) of the first energy management system107such as, for example, 12 VDC or less. Additionally or alternatively, at block402, the electronic processor210monitors for a switchgear relay failure associated with the switchgear relay circuit102. For example, the electronic processor210receives a certain command (e.g., a trip command) generated by the switchgear relay circuit102indicative of the failure.

At block404, the electronic processor210determines whether a LOP, a switchgear relay failure, or a similar event of interest has occurred in connection with the switchgear relay circuit102. As mentioned above, to provide such a determination, the electronic processor210utilizes one or more of the sensors235, information and/or a trip command from the electronic controller106, and/or, in some embodiments, according to a trip command received from another remote electronic communications device (for example, a management server of the electric power distribution system10).

The processor210returns to block402upon determining none of a LOP, a switchgear relay failure, or a similar event of interest has occurred. In instances where at least one of a LOP, a switchgear relay failure, or a similar event of interest has occurred, at block406, the electronic processor210actuates the changeover device108to disconnect the coil circuit112from the switchgear relay circuit102and connect the coil circuit112to the polarity control device110of the back-up trip circuit104. That is, at block406, the electronic processor210controls the changeover device108and/or, more generally, controls the back-up trip circuit104to change state (e.g., from the first circuit state to the second circuit state) to provide the second electrical connection and terminate the first electrical connection previously described. In this manner, the electronic processor210attempts to transfer control of the coil circuit112from main trip circuit105to the back-up trip circuit104.

At block408, the electronic processor210monitors a state of the changeover device108. In some examples, the electronic processor210initiates the monitoring simultaneously or in parallel with the operation(s) performed in connection with block406or, in other examples, prior or subsequent to such operation(s).

At block410, the electronic processor210determines whether a target state change of the changeover device108occurred in connection with the attempt performed at block406. For example, the electronic processor210detects that the changeover device108changed from the first circuit state to the second circuit state. In another example, the electronic processor210detects that the changeover device108remained in the first circuit state.

In instances where the changeover device108successfully changes state (sometimes referred to as “throwing over”), at block412, the electronic processor210controls, via the polarity control device110, the polarity of the coil circuit112to operate one or more (e.g., all) switch module(s)122A-122C of the switchgear120. In some examples, the electronic processor210actuates the h-bridge(s)116A-116C of the polarity control device110such that, when the coil circuit112is connected to the polarity control device110, the polarity of the coil(s)114A-114C is adjusted or changed (e.g., reversed and/or pulsed) upon connection to the respective h-bridge116A-116C, opening the interconnection and disconnecting the client source20or the resource(s)25from the electrical grid source15. In some scenarios where the system100is a multi-phase system, the electronic processor210adjusts, via all of the h-bridges116A-116C, polarities of the respective actuator coils114A-114C at substantially the same time (i.e., simultaneously).

In some instances (e.g., where the switchgear120is substantially mechanically driven), at block412, the electronic processor210directs the polarity control device110to apply a low energy electrical input (e.g., 1 joule or less) to the coil(s)114A-114C while maintaining the circuit polarity. As a result, in such instances the actuator128triggers the respective mechanism of the switchgear120to release the stored mechanical energy, opening the interconnection and disconnecting the client source20or the resource(s)25from the electrical grid source15.

When controlling polarity at block412, the electronic processor210advantageously utilizes electrical power stored by one of the first energy management system107, the second energy management system111, or a combination thereof. In some examples, the electronic processor210draws electrical power from the capacitor bank144in order to drive operation of the switch module(s)122A-122C.

In some embodiments, the electronic processor210is further configured to output an alert to a user to notify a user that the back-up trip circuit104has tripped. The electronic processor210, for example, may transmit, via the transceiver240, a notification to a user device and/or management server to indicate that the back-up trip circuit104was actuated. As another example, the electronic processor210may provide a visual indication (for example, via one or more LEDs) or an indication displayed on a display of the back-up trip circuit104, flipping an indication switch on a housing (not shown) of the switchgear system100.

In some examples, following either of a time delay (for example, approximately 30 milliseconds) or determining that the switchgear relay circuit failure or LOP is cleared (for example, based on information from the sensors245, the electronic controller106, and/or a command from another electronic communications device), the electronic processor210may actuate the h-bridges116A-116C to revert the polarity of the coils114A-114C back and actuate the changeover device108to reconnect the coil circuit112to the switchgear relay circuit102. The electronic processor210may maintain the connection between the polarity control device110and the coil circuit112via the changeover device108until the switchgear relay circuit failure or LOP is cleared. Alternatively, in some embodiments, the electronic processor210keeps the coils114A-114C open following block412and does not attempt to reclose.

On the other hand, in instances where the changeover device108remains in the first circuit state (e.g., due to circuitry malfunction) after one or more state change attempts is/are performed, at block414, the electronic processor210generates an alert (e.g., indicative of malfunction). For example, the electronic processor210provides a visual indication (e.g., via one or more LEDs) to warn personnel nearby the switchgear120. Additionally or alternatively, in another example, the electronic processor210transmits, via the transceiver240, a notification to a user device and/or management server to indicate a condition of the back-up trip circuit104.

Based on the provided description, a person of ordinary skill in the pertinent art will readily understand how to make various modifications and changes without any undue experimentation and without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the disclosure and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, features, examples, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass equivalents thereof.