Operation detection devices having a sensor positioned to detect a transition event from an overcurrent protection component and related methods

An operation detection device for an overcurrent protection component is provided. The overcurrent protection component has a closed state and an open state and outputs a transition event responsive to a transition between the closed state and the open state. The operation detection device includes a housing configured to attach to the overcurrent protection component. A sensor is positioned in the housing at a location selected to allow the sensor to detect the transition event. A switch circuit is operatively coupled to the sensor and is configured to generate an output signal indicating a change in state of the overcurrent protection component responsive to detection of the transition event by the sensor.

FIELD OF THE INVENTION

The present invention relates to power distribution network devices, and in particular, to operation detection devices for cable protectors or “limiters.”

BACKGROUND

In power distribution networks, there are typically many cable over current protection devices, such as limiters and fuses, that limit and/or even prevent cable damage due to over-current situations that may be caused by circuit overloads, inadvertent short circuit faults and/or the like. The responsible party (such as the utility company) may benefit if they know when these limiting devices operate, e.g., to open the respective electric circuit or link.

Conventional “blown fuse indicators” typically use a small, fusible wire that is electrically connected to a larger, primary fuse element. A spring-loaded flag or other indicia is held in a closed position by the fusible wire. When the fuse element opens a circuit in response to an over-current and/or over-voltage condition, the fusible wire is liquefied, and, consequently, the spring-loaded flag is deployed. However, fusible wires that are electrically integrated with the fuse element and release a spring-loaded indicator may not be easily installed on existing equipment (i.e., retrofitted) and/or may present difficulties with resettability.

SUMMARY OF EMBODIMENTS OF THE INVENTION

According to some embodiments of the invention, an operation detection device for an overcurrent protection component is provided. The overcurrent protection component has a closed state and an open state and outputs a transition event responsive to a transition between the closed state and the open state. The operation detection device includes a housing configured to attach to the overcurrent protection component. A sensor is positioned in the housing at a location selected to allow the sensor to detect the transition event. A switch circuit is operatively coupled to the sensor and is configured to generate an output signal indicating a change in state of the overcurrent protection component responsive to detection of the transition event by the sensor.

In further embodiments of the invention, the sensor is electrically isolated from the overcurrent protection component.

In other embodiments, the transition event includes one of a plurality of transition events having different associated types, and the switch circuit is further configured to identify ones of the associated types of transition events responsive to detection by the sensor. The types of transition events can include a short circuit transition event and/or an overload transition event. In particular embodiments, the sensor includes a plurality of sensors, and the plurality of sensors can include optical sensors, thermal sensors and/or acoustic sensors.

In further embodiments, the transition event includes a light burst emitted by the overcurrent protection component when the overcurrent protection component transitions from the closed state to the open state and the sensor is a photosensor. The sensor can be configured to detect the transition event responsive to the light burst when the light burst has a duration of less than about 500 millisecond.

In other embodiments, the transition event includes radiofrequency (RF) energy produced by an arc from the overcurrent protection component when the overcurrent protection component transitions from the closed state to the open state. The sensor can include an RF detector.

In other embodiments, the transition event includes infrared (IR) radiation produced by heat of an arc from the overcurrent protection component when the overcurrent protection component transitions from the closed state to the open state. The sensor can include an IR detector. In other embodiments, the transition event includes an acoustic impulse produced when the overcurrent protection component transitions from the closed state to the open state. The sensor can include an acoustic detector.

In further embodiments, the switch circuit further includes a transmitter configured to transmit the output signal indicating a change in state of the overcurrent protection component to provide a remote notification of detection of the transition event.

In still further embodiments, the device includes a light emitting device (LED) coupled to the housing. The switch circuit is configured to illuminate the LED responsive to detection of the transition event by the sensor to provide a local notification of detection of the transition event.

According to further embodiments, an overcurrent protection component assembly includes the overcurrent protection component and the operation detection device.

According to some embodiments, an operation detection device for an overcurrent protection component is provided. The overcurrent protection component has a closed state and an open state and outputs a transition event responsive to a transition between the closed state and the open state. A sensor is electrically isolated from the overcurrent protection component and positioned in a location selected to allow the sensor to detect the transition event. A switch circuit is operatively coupled to the sensor and is configured to generate an output signal indicating a change in state of the overcurrent protection component responsive to detection of the transition event by the sensor.

In some embodiments, the device further includes a housing configured to detachably mount the sensor to an overcurrent protection component and to position the sensor at the location selected to allow the sensor to detect the transition event.

In further embodiments, the location of the sensor is displaced from the overcurrent protection component.

According to some embodiments, methods of detecting an operation of an overcurrent protection component are provided. The overcurrent protection component has a closed state and an open state and outputs a transition event responsive to a transition between the closed state and the open state. The transition event is detected using a sensor that is electrically isolated from the overcurrent protection component. An output signal is generated indicating a change in state of the overcurrent protection component responsive to detection of the transition event by the sensor.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity.

It will be understood that, although the terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a “first” element discussed below could also be termed a “second” element without departing from the teachings of the present invention. The sequence of operations (or steps, e.g., illustrated in flowcharts) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

The present invention is described below with reference to block diagrams and/or flowchart illustrations of methods, apparatus (systems) and/or computer program products according to embodiments of the invention. It is understood that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, and/or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, create means for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

As will be appreciated by one of skill in the art, the invention may be embodied as a method, device, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.”

As illustrated in the embodiments ofFIG. 1, an operation detection device/overcurrent protection component assembly10includes an overcurrent protection component50, a strap or connector60and an operation detection device100. Ports20are electrically connected within the overcurrent protection component50and are connected to an electric circuit (not shown) via cables. The overcurrent protection component50includes a fuse element52and a transparent housing54. The operation detection device100is mounted to the overcurrent protection component50by a clamp or connector60. The overcurrent protection component50, which protects the electric circuit, has a closed state and an open state. The overcurrent protection component50outputs a transition event when the overcurrent protection component50transitions between the closed state and the open state. For example, the fuse element52opens or disconnects the electrical ports20to open the circuit in an over-current situation that may be caused by a circuit excessive overload, inadvertent short circuit fault and/or the like. When the overcurrent protection component50transitions between a closed state (in which the fuse element52connects the ports20) and an open state (in which the fuse element52disconnects the ports20), the overcurrent protection component50outputs a transition event, such as an electrical arc. The arc can produce an optical event, such as a light burst, thermal energy, radio frequency (RF) energy, infrared (IR) radiation, and/or acoustic impulses (sound waves).

As illustrated inFIGS. 2 and 4, the operation detection device100includes a sensor110, a variable resistor120, a light emitting diode (LED)130, a reset button140, an on/off button150, a switch circuit160, a power supply or battery170and a housing180. As shown inFIG. 3, the housing180includes access apertures110A,120A,140A and150A for the sensor110, the variable resistor120, the reset button140and the on/off button150, respectively. These components may be enclosed or covered to provide environmental seal of the detection device.

As shown inFIGS. 1-4, the housing180is configured to position the sensor110adjacent the transparent housing54of the overcurrent protection component50. The location of the sensor110can be selected so that the sensor110detects the transition event when the overcurrent protection component50transitions between a closed and an open state (Block300,FIG. 7). The switch circuit160is operatively connected to the sensor110and generates an output signal indicating a change in state of the overcurrent protection component overcurrent protection component50responsive to detection of the transition event by the sensor110(Block302,FIG. 7).

In some embodiments, the sensor110can be configured to detect one or more indicia of the electrical arc transition event, including optical indicia, heat, infrared (IR) radiation, radiofrequency (RF) radiation, acoustic energy (such as sound waves) and the like. In particular embodiments and as shown inFIGS. 1-4, the sensor110is electrically isolated and/or physically displaced from the overcurrent protection component50. Accordingly, electrical integration of the sensor110with the fuse element52is not provided in some embodiments of the present invention.

For example, the transparent housing54can transmit a flash of light from an electrical arc transition event in the fuse element52, and the sensor110can be a photosensor. In some embodiments, the housing54may be opaque, and/or the transition event can be detected without requiring an optical sensor, e.g., by using a heat sensor, IR sensor, RF sensor and/or acoustic sensor.

Accordingly, the switch circuit160of the operation detection device100can generate an output signal indicating a change in state of the overcurrent protection component50responsive to detection of the transition event by the sensor110when the fuse element52opens a circuit. For example, the sensor110can be electrically isolated and/or physically displaced from the fuse element52before and after the fuse element52outputs a transition event that opens a circuit due to an over-current condition. In the configuration illustrated inFIGS. 1-4, the housing180of the operation detection device100can be removably attached to existing overcurrent protection/limiter equipment without requiring electrical integration with the fuse element52. In some embodiments, the reset button140can reset the switch circuit160for additional usage.

For example, as illustrated inFIG. 5, the sensor110may include a phototransistor Q1and the switch circuit160may include a latching relay RLY. It will be understood that optical sensors are not limited to the illustrated phototransistor Q1. For example, a photodiode can be used. The phototransistor Q1is configured to detect and activate (“trigger”) by generating an output signal responsive to a flash of light that is emitted from the fuse element52(FIG. 1) when the fuse element52opens a circuit (breaks the connection between the ports20) to protect the circuit from an over-current condition.

The phototransistor Q1can have a response time sufficient to detect sub-millisecond light bursts. The activation of the phototransistor Q1can be used to switch a semiconductor device field effect transistor (FET) Q2, which switches the state of the latching relay RLY. A relay contact signal (output signal) from the latching relay RLY can be used to control local and/or remote notification of the status of the operation control device100. For example, the latching relay RLY can trigger illumination of the diode D2(corresponding to the LED130ofFIGS. 1-4) to provide a local notification signal indicating that the overcurrent protection component50is in the open state. In particular embodiments, the use of a blinking LED or LED circuit can reduce power consumption and/or increase the battery life of the battery170. In some embodiments, the latching relay RLY can trigger a remote notification of the status of the overcurrent protection component50, for example, by triggering a transmitter to transmit a signal to a remote device.

The latching relay RLY can remain in the “triggered” state until, for example, the latching relay RLY is reset by an operator by pressing the reset switch140ofFIG. 2(which corresponds to the reset switch component SW1ofFIG. 4). The reset switch140can be a magnetic reed or the like to support environmental sealing of the detection device100. In some embodiments, an additional LED D1can be used for testing and/or adjusting the detection device100.

In particular embodiments as shown inFIGS. 2,4and5, the sensitivity and/or false triggering of the device100can be controlled by the variable resistor120(corresponding to resistor R1inFIG. 5) and/or a potentiometer. However, in some embodiments, a fixed value resistor can be used. In various embodiments, the selection of the circuit design and component selection for the circuit, e.g., the circuit shown inFIG. 5, may result in a longer battery life, re-settable operation, and reduced maintenance such that the device100may be substantially maintenance free.

As illustrated inFIG. 1, the operation detection device100is mounted on the light transmissive housing54of the overcurrent protection component50so as to position the sensor110(which is located at the opening110A ofFIG. 3) in a location to detect transition events, such as over the fusible element52. For example, the overcurrent protection component50can be a Tyco Electronics Smart Limiter cable protector. In some embodiments, the sensitivity and/or false triggering of the device100can be controlled by physical light blockage by the housing180. As illustrated, the device100can be mounted on the overcurrent protection component50by a strap connector60; however, the device100can be mounted using various techniques, including a snap fit connection, separable or integrated clamps or the like.

Although embodiments of the current invention are illustrated with respect to the operation detection device100and the overcurrent protection component50, it should be understood that various modifications to the illustrated embodiments of the operation detection device100and the overcurrent protection component50may also be provided in some embodiments of the present invention. For example, although the operation detection device100is illustrated as a separate device that is detachably mounted to the overcurrent protection component50, it should be understood that the operation detection device100can be integrated with and provided in a single housing with the overcurrent protection component50in some embodiments. The operation detection device100illustrated inFIG. 2includes a power supply or battery170; however, it should be understood that the power supply can be provided by an external source, such as from another local circuit or the overcurrent protection component50itself.

Although embodiments according to the present invention are described with respect to the photosensor110being a phototransistor Q1inFIGS. 2-5, it should be understood that other types of optical and non-optical sensors can be used. In some embodiments, the housing54of the overcurrent protection component50is opaque, and/or the operation detection device100can detect a transition event without requiring photon/optical detection. For example, the detection of a transition event from the overcurrent protection component50can be through the detection of radiofrequency (RF) (such as broadband radiofrequency (RF)) energy produced by an arc generated by triggering of the fuse element52. In other embodiments, light reception and/or infrared (IR) (such as band filtered infrared (IR)) radiation due to the heat of the arc may be used for detecting the transition event. Further approaches include, for example, a time weighted change (e.g., integrator based) in the current flow through the overcurrent protection component50to detect sudden changes terminating at zero current flow and/or acoustic impulses (e.g., sound waves), such as acoustic impulses detected from the housing54of the overcurrent protection component50. It will also be understood that a combination of these varied detection approaches may be used in some embodiments of the present invention. Accordingly, RF detectors, IR detectors, and/or acoustic detectors (such as microphones) may be used to detect a transition event from the overcurrent protection component50.

Although the sensor110is illustrated as being positioned adjacent the overcurrent protection component50by an aperture110A, it should be understood that any suitable configuration can be used. If the sensor110is an optical sensor, any configuration suitable for the sensor110to detect light may be used. For example, the sensor110can be positioned inside the housing54and light can be transmitted to the sensor110via an optical fiber or other suitable light transmitter.

For example, as shown inFIG. 6, an operation detection device200includes one or more sensors210and a switch circuit260having a controller290and a transmitter295. The controller290is configured to analyze outputs from one or more of the sensors210, e.g., to increase the reliability/certainty of detection and/or to provide additional data about the type of fault triggering operation. In some embodiments of the present invention, the transition event is one of a plurality of transition events, and the controller290is further configured to identify one of the plurality of transition events responsive to detection by the sensor210. For example, the transition event signature may indicate a type or a potential cause of fault (e.g., a circuit overload or short circuit) which produces a characteristic profile, such as a time duration, photon flux and/or heat flux detected by the sensor210from a transition event from an overcurrent protection component (such as overload overcurrent protection component50inFIG. 1). For example, a short, bright arc from a fuse element can indicate a low impedance fault such as a direct short circuit whereas a low intensity arc may indicate a normal overload condition In some embodiments, the controller290can identify and provide as output to a user a likely transition event type from a plurality of potential transition events types.

Although the controller290is illustrated with respect to a plurality of sensors210, it should be understood that the controller290can be operatively connected to a single sensor while still providing operations such as identifying a transition event from a plurality of types of transition events in a overcurrent protection component responsive to detection by one (or more of) the sensor(s)210.

As further illustrated inFIG. 6, the transmitter295can be used to transmit an indication of the operation of an overcurrent protection component (e.g., whether the switch circuit260is in an active or inactive state) to a remote device such as a remote monitoring station.