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EP-4741838-A1 - DIGITAL SENSOR AND MONITORING SYSTEM FOR SWITCHGEAR PROTECTION

EP4741838A1EP 4741838 A1EP4741838 A1EP 4741838A1EP-4741838-A1

Abstract

A device for protecting, controlling, and monitoring electrical medium range switchgear or other electrical devices comprising use of a Rogowski coil embedded in the bottle of a switchgear and surrounding the Mains flow of current carrying voltage, a capacitive or similar voltage-like divider, also surrounding the Mains and extending around the bottle, and providing analog signals from those devices to an integrated circuit for conversion to digital signals after possible adjustment by look up tables stored on the integrated circuit, and then transmitting as output the digital signals to a data accumulator where the same are optionally time stamped and compared to one another, to a standard or to themselves at a different time.

Inventors

  • HACK, BRUCE

Assignees

  • Hack, Bruce

Dates

Publication Date
20260513
Application Date
20251027

Claims (14)

  1. An integrated and compact mechanism for protecting, monitoring and/or controlling a switchgear comprising at least a voltage and current flow provider device having a surrounding, insulating cylindrical bottle containing a Mains conductor passing therethrough comprising: a Rogowski coil closely surrounding and molded into said insulating cylindrical bottle for sensing and providing an analog signal of current passing through said Mains conductor; a capacitive or similar voltage divider-like device sensing and providing a proportional analog signal of the voltage of said Mains conductor and also closely surrounding and molded into said insulating cylindrical bottle, having a first direct electrical lead connected to said Mains conductor and a second direct electrical lead to ground; a shielded and integrated circuit board electrically connected to the analog outputs of the signals of both said Rogowski coil and said capacitive voltage divider-like device, capable of converting said analog signals to digital signals of the same, said integrated circuit board further comprising a stored look up table having calibrated indicia of digital signals based on a predetermined accurate set of values obtained from a known and verified standard, and said integrated circuit board further comprising a memory device, wherein said current and/or voltage digitally converted and calibrated signals from said look up tables are stored in said memory, as desired for further comparison and/or end use; and a data collector for at least some of said analog and/or said digital and/or said calibrated signals, optionally further comprising a means for time stamping said inputted set of said analog and/or digital and/or calibrated signal sets for comparing the same, over time or not; and said data collector being connected to electro- and/or mechanical means for modifying, controlling and/or disturbing the flow of current and/or voltage if certain predetermined conditions are met by said compared sets of signals or to a predetermined set of standard values of such signals.
  2. A mechanism as claimed in Claim 1 wherein said integrated circuit board is located within said switchgear and adjacent to the outer and insulative circumferential wall of said bottle.
  3. A mechanism as claimed in claim 2 wherein said capacitive or similar voltage divider -like device is superimposed over or embedded immediately beneath said Rogowski coil.
  4. A mechanism as claimed in claim 1 wherein 6 insulating cylindrical bottles are provided to said switchgear, each encircling a Mains conductor with current flow and voltage provided therethrough and each of said bottles being provided with said integrated and compact mechanism comprising said Rogowski coil and Capacitive or similar Voltage Divider-like devices and wherein said each of said integrated circuit boards direct their converted and calibrated look-up table digital signal outputs for analysis to a single data collector before or after providing the same to said memory device.
  5. A method of protecting, monitoring or controlling an electrical switchgear having one or more insulative bottles surrounding one or more Mains conductor power lines passing through each of said cylindrical insulative bottles, comprising the steps of: providing a Rogowski coil substantially immediately surrounding each of said cylindrical insulative bottle(s) which senses and transmits an analog signal corresponding to current flow through said Mains conductor; providing a capacitive or similar voltage divider-like device proximal to said insulative bottle(s) which senses and transmits an analog signal of the voltage passing hrough said Mains conductor, said capacitive or similar voltage divider-like device being in direct electrical contact with said Mains conductor passing through said cylindrical insulative bottle to which it is provided and to ground; providing and connecting an integrated and shielded circuit board proximal to each of said Rogowski coil(s) and/or said capacitive or similar voltage divider- like device(s) for receiving and converting said analog current and voltage signals to digital signals; and using a look-up table stored on said integrated and shielded circuit board for said digital signals to provide a calibrated indicia of said digital signal based on a predetermined set of values contained on said look up table, and then storing the calibrated indicia on a memory device for retrieval therefrom, as desired for further end use; and/or passing said calibrated digital signals to a data collector for optionally time stamping the same and for comparing at least one of said digital signal sets to a separately timed set of either or both of said voltage and/or said current passing through said Mains conductor passing through said bottle-like devices or to a standard for providing an electrical or electro-mechanical or mechanical action for protecting, monitoring or controlling an electrical switchgear.
  6. A method as claimed in Claim 5 wherein six bottles are provided for producing two sets of three phase electrical Mains conductors or pathways for said switchgear.
  7. A method as claimed in Claim 5 wherein time stamped digital signal sets of said Rogowski coil(s) and said capacitive or similar voltage divider(s) like devices of values of the current and/or voltage, respectively, passing through said Mains conductor(s) are used to monitor the switchgear and the protecting, monitoring and/or controlling of said switchgear if said digital signals, as calibrated by said look up tables on said integrated circuit, exceed or differ from a predetermined standard for said Mains conductors.
  8. A method as claimed in Claim 5 wherein multiple and separate parallel signal analyzing paths are provided within said integrated and shielded circuit board for converting said analog signals to digital signals with each but the last of such paths having a maximum which, if exceeded by either said current or said voltage analog signals, will pass the signal to the next upper maximum parallel path and adjacent range for conversion to a digital signal, with the next upper maximum and adjacent range having a greater maximum than the prior parallel path.
  9. An integrated circuit board device for use in protecting, monitoring and/or controlling electrical devices in the field having a voltage and current flow provider via a Mains conductor comprising: a Rogowski coil surrounding said voltage and current flow provider, said Rogowski coil providing an analog signal of current flow through said Mains conductor; a capacitive or similar voltage divider-like mechanism in close proximity to said voltage and current provider in said Mains conductor, having one lead in contact with said voltage and current flow provider and another lead connected to ground, said capacitive or similar voltage divider like mechanism providing an analog signal of voltage; analog to digital conversion means for converting said analog signals from both said Rogowski coil and said capacitive or similar voltage divider like mechanism to digital signals; an integrated circuit board electrically connected to the inputs of said analog to digital conversion means of both said Rogowski coil and said capacitive or similar voltage divider-like mechanism, said integrated circuit board being capable of analog to digital signal conversion and also having a look up table stored thereon for calibrating the resulting digital signals to a precisely calibrated set of the same based on previously obtained bench testing of a precisely known standard Mains conductor of voltage and current flow in comparison to said field-based voltage and current flow provider; and a means for electrically, mechanically, or electro-mechanically changing the state of said electrical device when said digital signals from said Rogowski coil and/or said capacitive or similar voltage divider-like mechanism change over time.
  10. An integrated circuit board device for use in protecting, monitoring and/or controlling electrical devices having a voltage and current flow provider therein as set forth in claim 9 further comprising a time stamping mechanism and a memory for retaining at least two time separated sets of said digital signals received from said Rogowski coil and said capacitive or voltage divider-like device.
  11. An integrated circuit board device for use in protecting, monitoring and/or controlling electrical devices having a voltage and current flow provider as claimed in claim 9 further comprising a memory means and a data collector mechanism for storing and allowing retrieval and analysis of digital signals from said memory.
  12. An integrated circuit board device for use in protecting, monitoring and/or controlling electrical devices having a voltage and current flow provider as claimed in claim 9 further comprising a memory means and a data collector mechanism for storing and allowing retrieval and analysis of digital signals from said memory of said digital signals.
  13. An integrated circuit board device for use in protecting, monitoring and/or controlling electrical devices having a voltage and current flow provider as claimed in claim 9 wherein said integrated circuit board device is embedded into the outside insulating circumferential wall of a bottle in a switchgear.
  14. An integrated circuit board device as claimed in claim 13 further comprising shielding for isolating said integrated circuit board device from stray signals from said voltage and current flow provider.

Description

Background of the Invention and Description of the Prior Art Medium voltage switchgear transmits and protects electrical power that is generally in the range of 1,001 to 40,000 volts and between about 100 to 5,000 amps. None of these ratings or values are of the kind that can be touched by human hands without severe injury or more likely resulting in death. Additionally, prior to the present invention, none of these devices can be directly monitored, protected, or metered. There is no "Direct" sensing that lets one know what amount of current and/or voltage is actually going through the switchgear/circuit breaker. Heretofore, and currently indirect, proportional measurements of the current and voltage in medium switchgear is provided in analog fashion, using voluminous and costly transformational devices. The present invention takes analog signals from newer low powered sensing devices, immediately converts the same via an integrated circuit to digital signals and then adds a time stamping so as to be able to compare this instantaneous time stamped value to other time stamped samples of the same sensor(s) or control values and/or to other sensed signal locations at both the same and differing temporal instances. A less expensive, less bulky and less costly system for controlling, monitoring and protecting electrical equipment in the nature of switchgear is the desired end result. Prior to the present invention, there was only "indirect" sensing that lets us know if all is OK with the circuit's voltage, amperage (and other characteristics) and if the circuit breaker or switchgear should stay closed (allowing current to flow) or if there is now a situation that is NOT OK and the circuit breaker should immediately trip open due to improper voltage and/or amperage suggesting an impending calamitous situation. These prior art devices are voluminous, heavy, expensive, and provide information in analog form. They are referred to as Current Transformers. It would thus be highly desirous to provide a lightweight, relatively inexpensive, and ultimately digital signal providing device for use with medium voltage switchgear. And, if the device so provided were "self-monitoring" then another significant advantage would be provided so that the owner/maintaining individual(s) of the switchgear could know whether there is a fault, a ground fault, a short circuit or if the sensor/gauge itself is in a failure mode and needs attention or replacement. The long applied state of the art in the electrical switchgear industry is to use current transformers (CTs), and voltage transformers (known interchangeably as VT's "Voltage" Transformers or PT's "Potential" Transformers) and connecting them to and around the Main's Power conductors in switchgear. Mains Power refers, in this context, to alternating current providing electric power that is delivered to and through the electric grid. These transforming devices (CTs, & VTs or PTs) can sense the condition of the Mains Power conductors and send out a much lower, yet proportional analog signal of the Main's values so that downstream metering, monitoring and protective relaying devices know what the electrical system conditions are and allow the Main's circuit breaker to act accordingly. These devices work well, but they are cumbersome, expensive, analog and not inherently self-monitoring as provided by the present invention. As an example - a 15,000 volt Mains conductor connection, which one cannot safely directly touch with a human hand, could be proportionally transformed (and thus is still in analog form) with a Potential Transformer down to a 120 V signal (similar to a house light bulb's voltage) that could then go into a meter and provide a somewhat accurate accounting of the ever- changing values of the system's voltage. A corresponding Current Transformer can monitor a Mains current of Thousands of amperes and produce on its proportional output a 5 amp analog signal which is now at a level such that it can be directly wired into a protection or metering type device. This meter or protective device could be connected to a controller which will then determine if action by the circuit breaker is needed or not. This prior art technique and these transformer devices are rugged, reliable, and accurate. They exist in many places. But, as mentioned, they are heavy, expensive, bulky and provide proportional, analog, output values. And, these analog signals will ultimately need digital conversion by the modern microprocessor-based relaying, metering, monitoring and control devices that such signals will be fed into. The prior mentioned devices (CTs & VT/PTs) represent the electrical power industry's goto technology for more than a hundred (100) years. For medium voltage sorts of switchgear applications which are meant to ascertain the real time system voltage and current ratings so as to make use of that real time metrological information for secure operation of the switchgear, CTs and V