Continuously monitored remote power shutoff

Abstract

A framework for continuously monitoring remote power shutdown. According to one aspect, a monitoring circuit (107, 207) is coupled to a power removal circuit (101). The monitoring circuit (107, 207) can generate an output signal indicating circuit integrity based on one or more electrical characteristics of the power removal circuit (101). A notification system (110) can be further coupled to the monitoring circuit (107, 207). The notification system (110) can generate a notification (112) based on the output signal.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 889,243, filed August 20, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to power management and, more particularly, to continuously monitored remote power shutdown. Background Art

[0004] Remote power shutoff (also known as emergency power off or EPO) is often provided as a safety measure to quickly disconnect power to a specific piece of equipment (e.g., a diagnostic imaging scanner) in the event of an emergency. Such an emergency event may occur in an immediately dangerous situation that needs to be quickly ended or avoided to prevent injury or damage. Remote actuators (e.g., remote power off or RPO, emergency power off or EPO) can be used to facilitate the remote removal of power and allow all power to be safely shut off from a central location.

[0005] Remote power shutdown can be achieved using either a continuously powered circuit or a non-continuously powered circuit. A continuously powered circuit requires continuous energization of the trip device. Unfortunately, this results in system shutdown during brief power losses and inoperable equipment or systems in the presence of a circuit fault. Furthermore, such designs may require additional hardware and costs that need to be added to maintain power. Higher-power circuits require additional current draw to maintain power to the device. This also requires increasingly larger components and multi-phase systems, which adds additional hardware requirements and hardware and operating costs.

[0006] On the other hand, a non-continuously powered circuit only applies power to the trip device during activation, removing power to the device. While this solution allows the device to continue operating during a circuit fault (e.g., a disconnection due to a wire break or coil burnout), the circuit fault remains unknown until an emergency shutdown requires it. This results in a failure to remove power during an emergency, creating a dangerous situation. Operational verification requires additional costs for testing, equipment downtime, and personnel. Summary of the Invention

[0007] A framework for continuously monitored remote power shutdown is described herein. According to one aspect, a monitoring circuit is coupled to a power removal circuit. The monitoring circuit can generate an output signal indicating circuit integrity based on one or more electrical characteristics of the power removal circuit. A notification system can be further coupled to the monitoring circuit. The notification system can generate a notification based on the output signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more complete appreciation of the present disclosure and its many attendant aspects will be readily obtained by reference to the following detailed description when considered in conjunction with the accompanying drawings.

[0009] Figure 1 An exemplary remote power shutdown system is shown;

[0010] Figure 2 Another exemplary remote power shutdown system is shown; and

[0011] Figure 3 An exemplary method of continuously monitoring for remote power shutdown is shown. DETAILED DESCRIPTION

[0012] In the following description, many specific details are set forth, such as examples of specific components, devices, methods, etc., in order to provide a thorough understanding of the implementation of the present framework. However, it will be clear to those skilled in the art that these specific details do not need to be adopted to practice the implementation of the present framework. In other instances, well-known materials or methods are not described in detail to avoid unnecessarily obscuring the implementation of the present framework. Although the present framework is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that the present invention is not intended to be limited to the specific form disclosed, but on the contrary, it is intended to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the present invention. In addition, for ease of understanding, certain method steps are depicted as separate steps; however, these separately depicted steps should not be interpreted as necessarily dependent on order in their execution.

[0013] A framework for continuously monitored remote power shutdown is described herein. According to one aspect, the framework includes monitoring circuitry that continuously monitors the circuit integrity of a non-continuously powered power removal circuit and provides automated notification of the circuit status. The framework provides the benefits of both continuously powered and non-continuously powered circuits without the associated problems, such as system unavailability during brief power loss, failure to remove power during an emergency due to a faulty power removal circuit, partial circuit monitoring, high operational and hardware costs, and the like.

[0014] The present framework advantageously provides power removal even in the event of a faulty power removal circuit. Additionally, the present framework continuously monitors all components in the power removal circuit, including those described herein (e.g., trip devices) as well as any additional components not described herein. Notification of any circuit fault or condition can be immediately issued. The present framework can ride through brief power losses, allowing the power removal circuit to remain operational for emergency power shutdown. Advantageously, there are no nuisance trips during brief power losses. Furthermore, minimal hardware and minimal additional power are required to implement the present framework. Furthermore, high reliability of the remote power shutdown function is achieved. These and other exemplary features and advantages are described herein.

[0015] Figure 1 An exemplary remote power shutdown system 100 is shown. Remote power shutdown system 100 is coupled to a powered device (or system) 103. Device 103 receives three-phase system power via power lines A, B, and C. It should be appreciated that although remote power shutdown system 100 is shown as a three-phase alternating current (AC) circuit, the present framework is also applicable to other types of circuits, including but not limited to single-phase, two-phase, split-phase, direct current (DC), or combinations thereof.

[0016] Device 103 can be any powered system that may require power removal or electronic shutdown, such as in an emergency. For example, device 103 can be an industrial vulcanizer, an industrial furnace, or an elevator. Device 103 can also be a medical imaging modality that acquires medical image data. This medical imaging modality can be a radiology or nuclear medicine imaging scanner. This medical imaging modality can acquire medical image data using magnetic resonance (MR) imaging, computed tomography (CT), spiral CT, x-ray, positron emission tomography (PET), PET-CT, fluoroscopy, ultrasound, or single photon emission computed tomography (SPECT). Other types of imaging modalities or devices can also be used.

[0017] In some implementations, the remote power shutdown system 100 includes a power removal circuit 101 coupled to a monitoring circuit 107. The power removal circuit 101 enables remote triggering of power shutdown of a powered device 103. In some implementations, the power removal circuit 101 includes a disconnect switch (or circuit breaker) 102 and an actuator 104 coupled to a trip device 106. When the actuator 104 is activated, control power becomes available to the trip device 106 and activates the trip device 106, which then activates the disconnect switch 102 (e.g., opens contacts), thereby removing system power to the device 103. Although Figure 1A single actuator 104 and a single trip device 106 are illustrated, but it will be appreciated that multiple instances of each may be provided. Additionally, multiple actuators other than the trip device 106 may be provided. Figure 1 One or more elements other than those depicted in FIG.

[0018] The disconnect switch 102 may include, but is not limited to, a power disconnect switch, a circuit breaker, contacts of a contactor, a relay, or a combination thereof. The actuator 104 may be, for example, a remote actuator such as an RPO or EPO button. The actuator 104 may include one or more actuator contacts (e.g., relay contacts, contactor contacts, circuit breaker auxiliary contacts), a solid-state transistor-based switch, or a combination thereof. For example, the actuator 104 may include a relay having a normally open (NO) contact actuated by a series of normally closed (NC) contacts in an RPO station.

[0019] Trip device 106 may include at least one electromagnetic coil that is non-continuously powered by control power lines 1 and 2 (L1, L2). Control power is applied to trip device 106 only when actuator 104 is activated. When actuator 104 is activated by the control power, trip device 106 receives the control power and actuates (or applies the control power to) disconnect switch 102, removing system power from device 103. Advantageously, because trip device 106 is non-continuously powered, a brief power loss does not actuate disconnect switch 102. Device 103 can ride through the brief power loss and remain operational during the brief power loss.

[0020] The trip device 106 may include, but is not limited to, a shunt trip, an electric circuit breaker, a contactor, a power shutoff circuit of an uninterruptible power supply (UPS), an undervoltage trip (UVT) circuit, or a combination thereof. It should be appreciated that the control power may be any type of power, such as alternating current (AC), direct current (DC), single-phase, multi-phase, or a combination thereof. The power may include any frequency or voltage level with appropriate selection of the component(s) of the monitoring circuit 107.

[0021] Monitoring circuit 107 is coupled to actuator 104 to continuously monitor power removal circuit 101 and provide an output signal that can indicate circuit integrity (or continuity). Monitoring circuit 107 advantageously enables device 103 to remain operational in the event of a fault in power removal circuit 101, while also providing high reliability of the power shutoff function in the event of an emergency. In some implementations, monitoring circuit 107 is coupled across normally open contacts of actuator 104 to provide a circuit integrity indication. Circuit integrity generally refers to the operability of power removal circuit 101 during activation of actuator 104, in the event of an emergency, such as requiring power shutoff of device 103. Circuit integrity can be affected by, for example, a line break and coil integrity and / or burnout in trip device 106.

[0022] Monitoring circuit 107 generates an output signal indicating circuit integrity based on one or more electrical characteristics of power removal circuit 101. This output signal may be, for example, a discrete signal representing the circuit state of power removal circuit 101. For example, when the output signal is "off" (or at a predetermined low level), it may indicate a fault condition. When the output signal is "on" (or at a predetermined high level), it may indicate an operational or normal condition. The electrical characteristics of power removal circuit 101 may include, but are not limited to, closed-loop current, closed-loop voltage, frequency, or a combination thereof.

[0023] In some implementations, monitoring circuit 107 includes a high-impedance (or low-current) device 108 to generate an output signal. High-impedance device 108 may include, but is not limited to, a high-impedance switch, a relay, an optical isolator, or a combination thereof. For example, high-impedance device 108 may be a solid-state relay with optical isolation. High-impedance device 108 may be de-energized in response to a fault occurring in power removal circuit 101, thereby generating a low output signal that is provided to notification system 110.

[0024] Monitoring circuit 107 is coupled to notification system 110 to automatically generate notification 112 based on the output signal. Notification system 110 can be a computer system, an alarm circuit, or any other system capable of generating notification 112 based on the output signal. Notification system 110 can be coupled to high-impedance device 108 to receive the output signal. Notification 112 can notify a user (or system) of the status of power removal circuit 101 (e.g., a fault state or an operational state). Notification 112 can include, for example, a visual alarm, an audible alarm, an electronic text message, an email message, or a combination thereof. Notification 112 can also be transmitted to a monitoring system (not shown) associated with powered device 103 to perform one or more actions in response to notification 112.

[0025] Advantageously, circuit faults throughout power removal circuit 101 can be continuously and automatically monitored by monitoring circuit 107. A user (or system) can be immediately notified of a fault condition in power removal circuit 101 so that action can be taken to correct the fault. Circuit 100 advantageously requires minimal hardware, thereby reducing cost, size, and installation effort. Additionally, minimal additional power is required, achieving high reliability of the remote power shutdown function in the event of an emergency.

[0026] Figure 2 Another exemplary remote power shutdown system 200 is shown. Remote power shutdown system 200 is coupled to a powered device 103. Remote power shutdown system 200 includes a power removal circuit 101 coupled to a monitoring circuit 207. Power removal circuit 101 enables remote triggering of power shutdown of powered device 103. In some implementations, power removal circuit 101 includes a disconnect switch (or circuit breaker) 102 and an actuator 104 coupled to a trip device 106. When contacts in actuator 104 close, current becomes available to trip device 106, which then opens contacts in disconnect switch 102, thereby removing system power from device 103.

[0027] Monitoring circuit 207 is coupled to actuator 104 to continuously monitor circuit 101 and provide an output signal indicating overall circuit integrity (or continuity) based on one or more electrical characteristics of power removal circuit 101. In some implementations, monitoring circuit 207 is coupled across normally open contacts of actuator 104 to provide a circuit integrity indication. Monitoring circuit 207 may include a high-impedance (or low-current) device 210 and a current transformer 212 coupled across actuator 104. High-impedance (or low-current) device 210 may include, for example, a current-limiting resistor, a relay coil, or a combination thereof. An ammeter 214 may be coupled across current transformer 212 to measure current and generate an output signal. The output signal of ammeter 214 indicates the circuit integrity (or circuit status) of power removal circuit 101. Thus, monitoring circuit 207 continuously and automatically monitors power removal circuit 101 (eg, trip device 106 ) and provides verification of circuit integrity while allowing powered device 103 to remain operational in the event of a circuit fault and providing high reliability of the power shutoff function in the event of an emergency.

[0028] Monitoring circuit 207 is coupled to notification system 110 to provide automatic user notification 112 of a circuit fault. Notification system 110 can be coupled to ammeter 214 to receive its output and generate user notification 112 based on the output signal. The output signal can be, for example, a discrete signal that indicates a circuit fault condition when "off" (or a predetermined low level) and an operational circuit condition when "on" (or a predetermined high level). The output signal can be monitored by notification system 110, which reports notification 112 to a user. User notification 112 can include, for example, a visual alarm, an audible alarm, an electronic text message, an email message, or a combination thereof.

[0029] Figure 3 An exemplary method 300 for continuously monitoring remote power shutoff is shown. It should be understood that the steps of method 300 may be performed in the order shown or in a different order. Additional, different, or fewer steps may also be provided. Furthermore, method 300 may be used Figure 1 System 100, Figure 2 The system 200 may be implemented as described above, a different system, or a combination thereof.

[0030] At 302, disconnect switch 102 is deactivated, and actuator 104 is also deactivated. At 304, system power and control power are applied to the remote power shutdown system (100 or 200). Device 103 receives system power via the deactivated (e.g., closed) disconnect switch 102. At 306, if there is no fault in power removal circuit 101, method 300 proceeds to 332. If there is a fault, method 300 proceeds to 308.

[0031] At 308, monitoring circuitry (107 or 207) generates a first predetermined level of an output signal based on one or more electrical characteristics of power removal circuitry 101. For example, high-impedance device 108 may change state from a high output signal to a low output signal in response to the occurrence of a fault. At 310, notification system 110 is activated in response to the first predetermined level of the output signal. At 312, in response to activation, notification system 110 generates notification 112 indicating a fault condition of power removal circuitry 101. During this fault event, trip device 106 is deactivated, and disconnect switch 102 remains deactivated (e.g., closed), allowing system power to be delivered to device 103. Consequently, device 103 remains powered and operational and does not shut down with power removal circuitry 101.

[0032] If no emergency event occurs, method 300 can proceed directly from 312 to 326. However, if an emergency event occurs at 321, device 103 needs to be shut down. At 322, system power can be removed from device 103 by activating disconnect switch 102 rather than remotely activating actuator 104 of power removal circuit 101. At 324, in response to activation of disconnect switch 102, system power is removed from device 103, and device 103 shuts down. The fault in power removal circuit 101 can be repaired during this emergency event.

[0033] At 326, the fault in the power removal circuit 101 is repaired, and the power removal circuit 101 is now fully functional. At 328, the disconnect switch 102 and the actuator 104 are deactivated. At 330, system power and control power are applied to the remote power shutoff system (100 and 200). System power is then delivered to the device 103.

[0034] At 332, when no fault exists in power removal circuit 101 or the previous fault has been repaired, a second predetermined level of output signal is generated based on one or more electrical characteristics of power removal circuit 101. For example, high-impedance device 108 may be activated and transmit a high output signal to notification system 110, indicating that power removal circuit 101 is operational. At 334, in response to the second predetermined level of output signal, notification system 110 is deactivated. At 336, in response to the deactivation, notification system 110 may transmit notification 112 indicating that the remote power shutdown system is operational (i.e., in an operational or normal state). Although no fault exists in power removal circuit 101, when actuator 104 is deactivated, trip device 106 is not powered. Disconnector 102 is thereby deactivated (e.g., closed), allowing system power to be delivered to device 103. Device 103 remains powered and operational. The trip device 106 may allow a small current to flow that powers the high impedance monitoring device 108 but does not actuate the disconnect switch 102 .

[0035] At 343, an emergency event occurs that requires device 103 to shut down. At 344, since there is no fault in power removal circuit 101, a user (or external device) can use actuator 104 to remove system power from device 103. At 348, notification system 110 is activated in response to, for example, the deactivation of high-impedance device 108 (e.g., the removal of control power). At 350, in response to receiving, for example, a low output signal from high-impedance device 108, notification system 110 transmits notification 112 indicating that actuator 104 is activated. During the emergency event, trip device 106 can receive control power and become activated, thereby activating (e.g., opening) disconnect switch 102. At 352, device 103 no longer receives system power and is successfully shut down.

[0036] Although the present framework has been described in detail with reference to exemplary embodiments, those skilled in the art will appreciate that various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention as set forth in the appended claims. For example, elements and / or features of different exemplary embodiments may be combined with each other and / or substituted for each other within the scope of this disclosure and the appended claims.

Claims

1. A system comprising: a power removal circuit for enabling remote triggering of power shutoff of a device coupled to the power removal circuit, wherein the power removal circuit is non-continuously powered; a monitoring circuit coupled to the power removal circuit, wherein the monitoring circuit continuously monitors the power removal circuit by generating an output signal indicative of circuit integrity of the power removal circuit based on one or more electrical characteristics of the power removal circuit; as well as A notification system is coupled to the monitoring circuit to receive the output signal, wherein the notification system generates a notification based on the output signal. 2 . The system of claim 1 , wherein the one or more electrical characteristics include closed-loop current, closed-loop voltage, frequency, or a combination thereof. 3 . The system of claim 1 , wherein the monitoring circuit is coupled across an actuator in the power removal circuit. The system of claim 1 , wherein the monitoring circuit comprises a high impedance device to generate the output signal.

5. The system of claim 4, wherein the high impedance device is deactivated in response to a fault occurring in the power removal circuit.

6. The system of claim 4, wherein the high impedance device comprises a high impedance switch, a relay, an optical isolator, or a combination thereof.

7. The system of claim 4, wherein the notification system is coupled to a high impedance device to receive the output signal.

8. The system of claim 1, wherein the output signal is a discrete signal representing a state of a circuit.

9. The system of claim 1, wherein the notification comprises a visual alarm, an audible alarm, an electronic text message, an email message, or a combination thereof.

10. The system of claim 1, wherein the monitoring circuit comprises a high impedance device and a current transformer coupled across the actuator in the power removal circuit.

11. The system of claim 10, wherein the monitoring circuit further comprises an ammeter coupled across a current transformer to generate the output signal.

12. The system of claim 1, wherein the power removal circuit comprises a disconnect switch and an actuator coupled to a trip device, wherein in response to activation of the actuator, the trip device is activated to actuate the disconnect switch, thereby removing system power to the equipment.

13. The system according to claim 12, wherein: Control power is applied to the trip device only when the actuator is activated.

14. The system of claim 12, wherein the trip device comprises a shunt trip, a motorized circuit breaker, a contactor, a power shutoff circuit of an uninterruptible power supply (UPS), an undervoltage trip (UVT) circuit, or a combination thereof.

15. A method comprising: continuously monitoring a power removal circuit by generating an output signal indicative of circuit integrity of the power removal circuit based on one or more electrical characteristics of the power removal circuit coupled to a device, wherein the power removal circuit is non-continuously powered and enables remote triggering of power shutoff of the device; as well as A notification is generated based on the output signal.

16. The method according to claim 15, further comprising: In response to a fault in the power removal circuit, a notification of the fault condition is generated based on the output signal, while a trip device in the power removal circuit is deactivated to allow system power to be delivered to the device.

17. The method according to claim 15, further comprising: In response to a fault in the power removal circuit, as well as an emergency event, system power is removed from the device by activating a disconnect switch in the power removal circuit.

18. The method according to claim 15, further comprising: In response to the absence of a fault in the power removal circuit, a notification of an operational status is generated based on the output signal.

19. The method of claim 15, further comprising: In response to the absence of a fault in the power removal circuit and an emergency event, system power is removed from the device by remotely activating an actuator in the power removal circuit.

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