The present invention relates generally to systems and methods related to monitoring circuit breakers and in particular to monitoring gas levels associated with the circuit breakers.
High voltage circuit breakers have an open state wherein electricity is not transmitted through the circuit breaker and a closed state wherein electricity is transmitted through the circuit breaker. To transition between these states electrical conductors are either brought into contact with each other or separated relative to each other. As the circuit breaker transitions between these states one or more undesired arcs of electrical energy may be transmitted between the electrical conductors.
It is known to house the electrical conductors within a housing that is filled with an arc quenching fluid. An exemplary arch quenching fluid is a gas containing SF6. The SF6 gas acts to reduce the occurrence or intensity of undesired arc events.
The occurrence of undesired arc events may contribute to the degradation of the circuit breaker components. Over time the circuit breaker components need to be replaced or the arc quenching gas needs to be refilled.
The present invention relates generally to systems and methods related to monitoring circuit breakers and in particular to monitoring gas levels associated with the circuit breakers.
In an exemplary embodiment of the present disclosure, a method of monitoring a circuit breaker provided in a gas filled enclosure is provided. The method comprising determining at least one gas characteristic of the gas in the enclosure; determining at least one fault arc energy characteristic of the circuit breaker; and forecasting with an electronic controller a maintenance event for the circuit breaker based on both the determined at least one gas characteristic and the determined at least one fault arc energy characteristic. In an example thereof, the at least one gas characteristic includes a gas density. In a variation thereof, the at least one fault energy characteristic includes an INT duty wherein I is a current passing through the circuit breaker, T is a time period, and N is in the range of about 1 to about 2. In another example thereof, the method further comprises the step of providing an indication of the forecasted maintenance event to a remote computing device. In still another example thereof, the step of forecasting the maintenance event includes determining an expected value of the at least one fault arc energy characteristic at a corresponding expected value of the at least one gas characteristic, the corresponding expected value of the at least one gas characteristic being less than the determined at least one gas characteristic. In yet still another example thereof, the step of forecasting the maintenance event includes the steps of determining an expected value of the at least one fault arc characteristic at a future time value, the expected value of the at least one fault arc characteristic being determined based on an expected value of the at least one gas characteristic at the future time value; determining if the expected value of the at least one fault arc characteristic causes a limit value for the at least one fault arc characteristic to be reached; and if the limit value is caused to be reached based on the expected value of the at least one fault arc characteristic then forecasting the maintenance event to occur at the future time value. In yet still another example thereof, the step of forecasting the maintenance event includes the steps of selecting a future time (Ti) to evaluate for a potential maintenance event; determining an expected fault arc energy ( ) at the future time (Ti) based on an expected value of the at least one gas characteristic, wherein N is a number of future arc events and (I2T)j is an expected fault arc energy for the jth arc event; determining a cumulative fault arc energy based on a historical fault arc energy and the expected fault arc energy; and comparing the cumulative fault arc energy with a limit to determine if the future time (Ti) corresponds to a maintenance event. In a further example thereof, the step of forecasting the maintenance event includes the steps of determining a future time whereat the at least one fault arc characteristic of a first arc event corresponds to a maintenance event. In a variation thereof, the at least one gas characteristic at the future time being determined based on a trend of the at least one gas characteristic and the at least one fault arc characteristic of the first arc event is based on the at least one gas characteristic at the future time. In still a further example thereof, the step of forecasting the maintenance event includes the steps of determining a future time whereat the at least one fault arc characteristic of a plurality of arc events correspond to a maintenance event. In a variation thereof, the at least one gas characteristic at the future time being determined based on a trend of the at least one gas characteristic and the at least one fault arc characteristic of the plurality of arc events is based on the at least one gas characteristic at the future time. In a further variation thereof, the plurality of arc events are clustered at the future time. In another variation thereof, the plurality of arc events are spaced apart between a current time and the future time. In yet still another example, the step of forecasting the maintenance event includes the steps of determining a number of future arc events within a time period prior to a maintenance event. In a variation thereof, the number of future arc events being based on a decreasing trend of the at least one gas characteristic. In another variation thereof, the number of future arc events being based on the at least one gas characteristic being set to a first value.
In another exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker being monitored by at least one current sensor operatively coupled to the circuit breaker and being provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one current sensor and the at least one gas sensor. The monitoring unit including an electronic controller configured to forecast a maintenance event for the circuit breaker based on both the determined at least one gas characteristic and the determined at least one fault arc energy characteristic. In an example thereof, the system further comprises a visual indicator which provides a visual indication of a plurality of conditions associated with the circuit breaker. In a variation thereof, the visual indicator toggles between an indication of the remaining contact life of the circuit breaker and an indication of the gas density surrounding the circuit breaker.
In yet another exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker being monitored by at least one current sensor operatively coupled to the circuit breaker and being provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one current sensor and the at least one gas sensor, the monitoring unit including an electronic controller configured to forecast a maintenance event for the circuit breaker; and a visual indicator which provides a visual indication of a plurality of conditions associated with the circuit breaker. The visual indicator toggles between an indication of the remaining contact life of the circuit breaker and an indication of the gas density surrounding the circuit breaker.
In still yet another exemplary embodiment of the present disclosure, a method of controlling a circuit breaker provided in a gas filled enclosure is provided. The method comprising determining at least one gas characteristic of the gas in the enclosure; determining at least one fault arc energy characteristic of the circuit breaker; and preventing an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker, the subsequent arc event being determined based on both the determined at least one gas characteristic and the determined at least one fault arc energy characteristic. In an example thereof, the at least one gas characteristic includes a gas density. In a variation thereof, the at least one fault energy characteristic includes an INT duty wherein I is a current passing through the circuit breaker, T is a time period, and N is in the range of about 1 to about 2.
In still another exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker being monitored by at least one current sensor operatively coupled to the circuit breaker and being provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one current sensor and the at least one gas sensor, the monitoring unit including an electronic controller configured to prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker, the subsequent arc event being determined based on both the determined at least one gas characteristic and the determined at least one fault arc energy characteristic.
In still a further exemplary embodiment of the present disclosure, a method of monitoring a circuit breaker provided in a gas filled enclosure is provided. The method comprising determining an initial mass of a gas of the gas filled enclosure; receiving an initial density of the gas of the gas filled enclosure from a density sensor; receiving a first density of the gas of the gas filled enclosure from the density sensor, the first density corresponding to a first instance in time; and determining with an electronic controller a gas loss mass of the gas of the gas filled enclosure at the first time based on the initial mass of the gas, the initial density of the gas, and the first density of the gas. In an example thereof, the method further comprises the step of determining if the density of the gas at the first time is less than the initial density of the gas by a threshold amount.
In yet another exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker being monitored by at least one current sensor operatively coupled to the circuit breaker and being provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one current sensor and the at least one gas sensor. The monitoring unit including an electronic controller configured to at least one of forecast a maintenance event for the circuit breaker and prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker; and a port to receive a portable memory device, the portable memory device including at least one script to at least one of upload information to a memory associated with the electronic controller and download information from the memory associated with the electronic controller. In one example thereof, the portable memory device includes at least one script to be executed when the portable memory device is coupled to the port. In a variation thereof, a first script is an Alarm Reset script configured to cause the electronic controller of the monitoring unit to reset at least one active alarms. In another example, the portable memory device includes a script selection input 170 which is actuatable from an exterior of the portable memory device. The script selection input having a plurality of settings each corresponding to a unique script. In a further example, the electronic controller forecasts the maintenance event based on both the determined at least one gas characteristic and the determined at least one fault arc energy characteristic. In still a further example, the subsequent arc event is determined based on both the determined at least one gas characteristic and the determined at least one fault arc energy characteristic.
In a further exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker being monitored by at least one sensor is provided. The system comprising a monitoring unit operatively coupled to the at least one sensor. The monitoring unit including an electronic controller based on input from the at least one sensor being configured to at least one of forecast a maintenance event for the circuit breaker and prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker; and at least one sensor connection adapted to couple to the at least one sensor, wherein when the at least one sensor is coupled to the at least one sensor connection the electronic controller configures the at least one sensor has one of an analog sensor and a digital sensor and verifies the presence of the at least one sensor. In an example thereof, if the at least one sensor is not providing a signal the electronic controller initiates an alarm. In another example thereof, the electronic controller records a plurality of readings from the at least one sensor and if a present readings differs from at least one prior reading by more than a threshold amount the electronic controller initiates an alarm.
In still a further exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one sensor. The monitoring unit including an electronic controller based on input from the at least one gas sensor being configured to at least one of forecast a maintenance event for the circuit breaker and prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker. The electronic controller records measurement readings received from the at least one gas sensor over a first calculation period, determines a trend line for the measurement readings, a confidence level for the trend line, and based on a characteristic of the trend line and the confidence level determines if an alarm condition is present.
In yet still a further exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one sensor. The monitoring unit including an electronic controller based on input from the at least one gas sensor being configured to at least one of forecast a maintenance event for the circuit breaker and prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker. The electronic controller records measurement readings received from the at least one gas sensor over a first calculation period and over a second calculation period, the second calculation period including the first calculation period; determines a first trend line for the measurement readings of the first calculation period; determines a second trend line for the measurement readings of the second calculation period; selecting one of the first trend line and the second trend line; and forecasting the maintenance event based on a characteristic of the selected trend line.
In another exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one sensor. The monitoring unit including an electronic controller based on input from the at least one gas sensor being configured to at least one of forecast a maintenance event for the circuit breaker and prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker, wherein the electronic controller determines a fill event wherein additional gas is provided to the interior of the enclosure based on measurement readings from the at least one gas sensor. In an example thereof, the electronic controller records measurement readings received from the at least one gas sensor over a first calculation period and over a second calculation period, the second calculation period including a more current measurement reading than the first calculation period; determines a first mean density value for the first calculation period; and determines a second mean density value for the second calculation period, wherein the fill event is determined based on the second mean density value exceeding the first mean density value.
In yet another exemplary embodiment of the present disclosure, a monitoring system for a circuit breaker provided in an interior of a gas filled enclosure being monitored by at least one gas sensor in fluid communication with the interior of the gas filled enclosure is provided. The system comprising a monitoring unit operatively coupled to the at least one sensor. The monitoring unit including an electronic controller based on input from the at least one gas sensor being configured to at least one of forecast a maintenance event for the circuit breaker and prevent an operation of the circuit breaker if a subsequent arc event corresponds to a potential failure of the circuit breaker; a fill valve being in fluid communication with the interior of the gas filled enclosure; and a volumetric flowmeter operatively coupled to the electronic controller and located to monitor an amount of gas being passed through the fill valve to the interior of the gas filled enclosure. In an example thereof, the volumetric flowmeter is supported by a pressurized gas supply coupled to the fill valve. In another example, the volumetric flowmeter is supported by the enclosure.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings.
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure. The exemplification set out herein illustrates embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, which are described below. The embodiments disclosed below are not intended to be exhaustive or limit the invention to the precise form disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. It will be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated devices and described methods and further applications of the principles of the invention which would normally occur to one skilled in the art to which the invention relates.
Referring to
As shown in
Circuit breaker controls 198 activates a trip coil 196 which permits circuit breaker 102 to transition to the open state of
As circuit breaker 102 transitions from the closed state of
Enclosure 122 provides a generally sealed volume around the connection between first conductive element 104 and second conductive element 106. The gas 124 in enclosure 122 does over time leak from the interior of enclosure 122 to the exterior of enclosure 122. As shown in
Referring to
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In one embodiment, operational software 146 includes communication software for handling data transfer between controller 142 and other devices, such as portable memory device 150 and remote computing device 152. Exemplary remote computing devices include personal electronic devices, smartphones, laptops, desktops, and other suitable computing devices. In the illustrated embodiment, portable memory device 150 is a device including a memory 154, a controller 156, and a universal serial bus (“USB”) connector 158. The USB connector 158 interfaces with a USB connector 160 accessible from an exterior of enclosure 140 to permit the communication of information from one of controller 142 and controller 156 to the other of controller 142 and controller 156. In one embodiment, information stored in memory 154 is uploaded to controller 142 for execution and/or storage on memory 144. In one example, settings are uploaded to controller 142 so that multiple monitoring systems 100 have the same settings. In one embodiment, information stored in memory 144 is downloaded to memory 154 of portable memory device 150. Although a USB connection is illustrated other suitable types of connection between a portable memory device 150 and controller 142 may be utilized. In one embodiment, a technician carries a unique portable memory device 150 for each monitoring system 100.
Referring to
In one embodiment, portable memory device 150 includes a script selection input 170 which is actuatable from an exterior of portable memory device 150. With script selection input 170, an operator may select the appropriate script to be executed by controller 142. In one embodiment, the script selection input has a plurality of settings each corresponding to a unique script. In one embodiment, memory 154 includes identification data 172 which is used to identify portable memory device 150 to controller 142. The script executed and the identity of the portable memory device 150 may be logged by controller 142 in a database, such as monitoring database 174, stored on memory 144 so that a record is kept of interactions with controller 142. In this manner, it is possible to determine who cleared alarms associated with monitoring system 100.
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In one embodiment, controller 142 has an associated IP address which is accessible by remote computing device 152 through a network. In the illustrated embodiment, an RS-232 port 176 of monitoring system 100 is coupled to a local area network 177 and one or both of an RS-485 port 178 and an Ethernet port 180 is coupled to one or both of a local area network 177 and a wide area network 181. Remote computing device 152 is coupled to monitoring system 100 through one of local area network 177 and wide area network 181. In one example, one of local area network 177 and wide area network 181 has access to the Internet and remote computing device 152 couples to the one of local area network 177 and wide area network 181 through the Internet.
In one embodiment, the logged data in monitoring database 174 is made available to remote computing device 152 as formatted XML data through a web interface 182. The data may then be stored on a memory 184 associated with remote computing device 152.
Referring to
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If the sensor is an analog sensor, controller 142 determines based on the received information the units of measure for the sensor, as represented by block 306. This information is stored in memory 144 for use in future calculations based on the sensor output. The controller 142 next determines based on the received information the upper and lower signal limits of the sensor and the corresponding value of the limits in a unit of measure, as represented by block 310. The controller also determines based on the received information the method of scaling from the sensor signal to the unit of measure, as represented by block 312. In the same manner as digital sensors, controller 142 next verifies the presence of the sensor, as represented by block 308. In one embodiment, the controller 142 checks to see if a signal is being provided by the sensor. If there are no additional sensors, controller 142 moves onto a sensor monitoring mode of operation, as represented by blocks 314 and 316.
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If a sensor signal is provided, controller 142 receives the sensor reading, as represented by block 340, and records an indication of the sensor reading in monitoring database 174, as represented by block 342. In one embodiment, the raw sensor reading is recorded in monitoring database 174. In one embodiment, a density value and a temperature value based on the raw sensor reading is recorded in monitoring database 174. The controller 142 determines if the sensor reading is out of range, as represented by block 344. If the sensor reading is out of range, a time-stamped “SENSOR SIGNAL OUT OF RANGE” alarm is logged in monitoring database 174, as represented by block 346. Controller 142 provides an indication of the alarm, as represented by block 348. Exemplary indications include visual indications at the location of monitoring system 100, audio indications at the location of monitoring system 100, an alert sent to remote computing device 152, and other exemplary indicators. In one embodiment, a relay shall close causing monitoring system 100 to provide a remote notification and an indicator 196 will be activated. An exemplary indicator 196 is a LED 199 on a face of monitoring system 100 shall light up (see
If the sensor reading is in range, the controller 142 determines if the sensor reading change from prior readings is within limits, as represented by block 350. If the sensor reading change is outside of the limits, a time-stamped “ERRATIC SENSOR” alarm is logged in monitoring database 174, as represented by block 352. In one embodiment, an erratic sensor alarm is set when the density measurements (examines multiple samples) deviate up and down by a significant amount, but the average (mean) of the samples does not show a significant (typically downward) trend. Controller 142 provides an indication of the alarm, as represented by block 354. Exemplary indications include visual indications at the location of monitoring system 100, audio indications at the location of monitoring system 100, an alert sent to remote computing device 152, and other exemplary indicators. In one embodiment, a relay shall close causing monitoring system 100 to provide a remote notification and an indicator 196 will be activated. An exemplary indicator 196 is a LED 199 on a face of monitoring system 100 shall light up (see
In one embodiment, controller 142 causes for each sensor 192 the present density (& temperature) “MEASUREMENTS” to be recorded in monitoring database 174 as a status log at regular intervals. In one embodiment, the interval may be set between two hours to twenty-four hours. The interval time may be a user selected parameter specified in settings file 166. In one embodiment, monitoring database 174 maintains about 5000 records in the status log of monitoring database 174. When the status log is filled, the oldest data entries shall be deleted following a first-in first-out methodology.
Controller 142 examines the recorded data to determine if a “LOW DENSITY WARNING” or a “LOW DENSITY ALARM” is present. In one embodiment, if a first threshold number of consecutive “MEASUREMENTS” for a sensor is equal to or below a first programmed threshold value, a “LOW DENSITY WARNING” will be logged in monitoring database 174, and an indicator 196 will be activated. An exemplary indicator 196 is the LED 199 on a face of monitoring system 100 which shall light up (see
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If the calculation period has ended, a trend line is determined for the calculation period as represented by block 406. In one embodiment, the trend line is a best fit line to the sensor density values. Time-stamped values of the slope of the trend line and a fit characteristic or confidence factor of the trend line are recorded in monitoring database 174, as represented by block 408. Controller 142 determines if the recorded slope is equal to or greater than a programmed Daily Density Trend Alarm Limit. If the recorded slope is equal to or greater than the limit (meaning the gas density is decaying at an unacceptable rate), represented by block 410, and the Confidence Level is 50% or higher (meaning the gas density meets a first measure of linearity), represented by block 412, a “DAILY DENSITY TREND ALARM” will be logged in monitoring database 174, as represented by block 414. Controller 142 provides an indication of the alarm, as represented by block 416. Exemplary indications include visual indications at the location of monitoring system 100, audio indications at the location of monitoring system 100, an alert sent to remote computing device 152, and other exemplary indicators. In one embodiment, a relay shall close causing monitoring system 100 to provide a remote notification and a LED 199 on a face of monitoring system 100 shall light up (see
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In one embodiment, at spaced apart time intervals (as an example every day), monitoring system 100 determines an average density for each time period and then determines a mass of the gas in enclosure 122 for that time period by multiplying the volume of the enclosure 122 by the average density. By accumulating the mass loss over a plurality of time periods, a mass loss across the multiple time periods may be determined.
If the calculation period has ended, a trend line is determined for the calculation period as represented by block 446. In one embodiment, the trend line is a best fit line to the sensor density values. Time-stamped values of the slope of the trend line and a fit characteristic or confidence factor of the trend line are recorded in monitoring database 174, as represented by block 448. Controller 142 determines if the recorded slope is equal to or greater than a programmed Weekly Density Trend Alarm Limit. If the recorded slope is equal to or greater than the limit (meaning the gas density is decaying at an unacceptable rate), represented by block 450, and the Confidence Level is 25% or higher (meaning the gas density meets a first measure of linearity), represented by block 452, a “WEEKLY DENSITY TREND ALARM” will be logged in monitoring database 174, as represented by block 454. Controller 142 provides an indication of the alarm, as represented by block 456. Exemplary indications include visual indications at the location of monitoring system 100, audio indications at the location of monitoring system 100, an alert sent to remote computing device 152, and other exemplary indicators. In one embodiment, a relay shall close causing monitoring system 100 to provide a remote notification and a LED 199 on a face of monitoring system 100 shall light up (see
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In one embodiment, the following data was logged by monitoring system 100. Once a minute the Minute Array is appended. Once an hour the Hour Array is appended, a Daily Density Trend is determined; a Daily Trend Confidence Level is determined; and a Low Density Alarm Forecast is determined. Once per day the Weekly or Monthly Density Trend is determined and a Weekly/Monthly Trend Confidence Level is determined. A Status Log is determined at a given interval (exemplary intervals being every 2-24 hours); a Present Density is determined; a Present Temperature (if available) is determined; a Present Daily Density Trend is determined; a Present Daily Trend Confidence Level is determined; a Present Weekly/Monthly Density Trend is determined; and a Present Weekly/Monthly Trend Confidence Level is determined.
In addition, the occurrence and time information (Date and Time) of the following alarms are logged: Loss of Sensor Signal Alarm, Sensor out of Range Alarm, Erratic Sensor Alarm, Daily Density Alarm including Daily Density Trend and Daily Trend Confidence Level, Weekly/Monthly Density Alarm. In one embodiment, monitoring system 100 has an associated printer 191 through which an operator may obtain log reports, an SF6 report, and alarm reports, and other suitable reports. Exemplary information in the SF6 report may include a measure of SF6 mass loss from the enclosure.
Referring to
In the embodiment, shown in
A pressurized gas reservoir 582 may be coupled to each of valves 580A-C. The pressurized gas reservoir 582 provides additional gas to the interior of the enclosure 122 to which it is coupled (when valve 580 is in the first configuration) to increase the density of the gas within the interior of the enclosure 122.
A respective volumetric flowmeter 584A-C is coupled to each of valves 580A-C. The volumetric flowmeter 584 associated with the valve 580 to which the pressurized gas reservoir is coupled monitors an amount of gas that is flowing from the pressurized gas reservoir to the interior of the enclosure 122. This provides the operator with the amount of gas that has been delivered to the enclosure 122. In one embodiment, the volumetric flowmeter 584 provides an indication of the amount of gas that has been delivered to the enclosure to the controller 142 of monitoring system 100. In this manner, monitoring system 100 is able to track the amount of gas delivered to the enclosures 122A-C it is monitoring. In one embodiment, this information is stored in monitoring database 174. An exemplary volumetric flowmeter is the TS-VFM flow meter available from Franklin Fueling Systems located in Madison, Wis. In one embodiment, if the volume of enclosure 122 is known, then monitoring a change in gas density in enclosure 122 during delivery of gas may be used to determine the amount of gas delivered to the enclosure 122.
Referring to
In one embodiment, in addition to monitoring the gas density within enclosure 122, monitoring system 100 also monitors one or more characteristics of the current flowing from first power line 108 to second power line 110. In one embodiment, the current monitoring processes are described in U.S. Pat. No. 4,977,513, the disclosure of which is expressly incorporated by reference herein. An exemplary embodiment of the monitoring system 100 is provided in U.S. Provisional Application Ser. No. 61/448,585, the disclosure of which is expressly incorporated by reference herein.
Referring to
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In one embodiment, a first portion 186A of the LEDs 188A-F are green in color. A second portion 186B of the LEDs 188G and 188H are yellow in color. A third portion 186C of the LEDs 188I and 188J are red in color.
In one embodiment, visual indicator 185 provides a visual indication of the remaining contact life as follows. All of LEDs 188 are illuminated to indicate full 100% contact life is available. As contact life is reduced the number of green LEDs illuminated decreases. The transition from the green LEDs to the yellow LEDs occurs at a danger setpoint for INT duty. As such, when none of the green LEDs are illuminated, but the yellow and red are then the contact life has reached a danger zone. The transition from yellow LEDs to red LEDs occurs at 0% contact life remaining. As such, when only the red LEDs are illuminated the contact life is at 0%. When the upper red LED is also not illuminted then the contact life is 25% over its limit. When none of the LEDs are illuminated then the contact life is 50% over its limit. In one example, when in the yellow zone, all illuminated LEDs 188 flash slowly and when in the red zone, all illuminated LEDs flash quickly.
In one embodiment, visual indicator 185 provides a visual indication of the gas density as follows. The LEDs 188 provide a range of density values. Each LED 188 corresponds to a density level. When the determined density is at a given level, the respective LED 188 is illuminated. In one embodiment, the transition to the yellow LEDs occurs at a warning density and the transition to the red LEDs occurs at a danger density. The warning density and the danger density being programmable values.
Referring to
Based on the at least one gas characteristic 702 and at least one fault arc energy characteristic 704, controller 700 determines a forecast for a maintenance event, as represented by block 706. In one embodiment, controller 700 determines a forecast for a maintenance event based on at least two gas characteristics, such as density and temperature. The controller 700 provides an indication of the forecasted maintenance event, as represented by block 762. Exemplary indications include visual indications, audio indications, tactile indications, communications to remote computing devices, and other suitable ways of providing a notification of a forecasted maintenance event. Exemplary visual indications include lights, gauges, information provided on a display, printed communication, faxed communication, and other indications perceivable by sight. Exemplary audio indications include audio tones or alarms produced by a speaker and other suitable indications perceivable by hearing. Exemplary tactile indications include a vibrating member and other suitable indications perceivable by touch. Communications to remote computing devices include any type of electronic data transfer over a serial connection, a wired network, a wireless network, or any other suitable connection between the controller and the remote computing device. Exemplary types of electronic data transfer include e-mail messages, instant messages, text messages, providing data for storage on a remote memory, and other suitable types of data transfer.
Referring to
Controller 700 has access to a memory 710. In one embodiment, memory 710 includes the same information as memory 144. Memory 710 is a computer readable medium and may be a single storage device or may include multiple storage devices, located either locally with controller 700 or accessible across a network. Computer-readable media may be any available media that may be accessed by controller 700 and includes both volatile and non-volatile media. Further, computer readable-media may be one or both of removable and non-removable media. By way of example, computer-readable media may include, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store the desired information and which may be accessed by controller 700.
Controller 700 executes maintenance event forecasting software 732 stored on the memory 710. Memory 710 further includes communications software, if controller 700 has access to a network 720, such as a local area network, a public switched network, a CAN network, any type of wired network, and any type of wireless network. An exemplary public switched network is the Internet. Exemplary communications software 112 includes e-mail software, internet browser software, and other types of software which permit controller 700 to communicate with other computing devices 730 across a network. Exemplary computing devices 730 include personal computers, smart phones, handheld computing devices, and other types of computing devices.
Memory 710 includes maintenance event forecasting software 732. Although described as software, it is understood that at least portions of the maintenance event forecasting software 732 may be implemented as hardware. As explained herein, maintenance event forecasting software 732 based on a plurality of inputs determines a future date for a maintenance event related to circuit breaker 102. Also, as explained herein maintenance event forecasting software 732 may reference one or more of historical gas density data 734, maintenance event variable 736, fault arc energy values based on gas density 738, and historical fault arc energy data 740.
Historical fault arc energy data 740 is a measure of the amount of fault arc energy that circuit breaker 102 has experienced to date. Historical gas density data 734 provides gas density readings taken over time. Referring to
The fault arc energy values based on gas density values 738 defines the relationship between gas density and fault arc energy. Referring to
Turning to
Maintenance event forecasting software 732 selects an initial time (Ti) in the future to evaluate for a potential maintenance event, as represented by block 764. As explained herein, if a forecasted maintenance event is not triggered at initial time (Ti), maintenance event forecasting software 732 increments the time period (i=i+1) to evaluate a time further in the future, as represented by block 774. In one embodiment, maintenance event forecasting software 732 increments by days. In one embodiment, maintenance event forecasting software 732 increments by weeks. Any suitable time block may be used for the incrementing. In one embodiment, maintenance event forecasting software 732 selects an initial time that is farther in the future and if a potential maintenance event is triggered at the initial time, decrements back towards the present day to determine the onset of the potential maintenance event.
At the time (Ti) maintenance event forecasting software 732 determines the expected fault arc energy for each future arc event based on the expected SF6 gas density at the projected time for the arc event, as represented by block 766. As explained in the scenarios below, for multiple arc events, one or more may be at times other than Ti. The expected SF6 gas density at a projected time is determined by maintenance event forecasting software 732 through an analysis of the historical gas density data. In one embodiment, maintenance event forecasting software 732 determines a linear regression of the historical gas density data and extrapolates that relationship out to the projected time. In the illustrated embodiment, the expected fault arc energy for each future arc event based on the expected SF6 gas density at the projected time for arc event may be expressed as:
wherein N is the number of future arc events, (I2T)j is the expected fault arc energy for the jth event, and (I2T)expected is the total expected future fault arc energy for all of the future arc events. In one embodiment, (I2T)j is determined from the look-up table of the fault arc energy values based on gas density 738. In one embodiment, wherein the circuit breaker 102 is a part of a three phase system, the look-up table 752 includes the highest potential I, phase to ground. In one embodiment, the value for (I2T)j determined from look-up table 752 is scaled based on the travel time or arc time associated with the historical current data 740. For example, look-up table 752 may be based on an arc time of x, but it is observed by maintenance event forecasting software 732 that the prior arc time for circuit breaker 102 was 1.2×. In this situation, maintenance event forecasting software 732 may scale the value for (I2T)j determined from look-up table 738. In one example, the scaling is a linear scaling.
Once the total expected future fault arc energy for all of the future arc events (N) is determined, maintenance event forecasting software 732 determines the total fault arc energy for time (Ti), as represented by block 768. In the illustrated embodiment, the total fault arc energy for time (Ti) may be expressed as:
(I2T)total(I2T)historic+(I2T)expected (2)
wherein (I2T)total is the total fault arc energy for the circuit breaker at time Ti, (I2T)historic is the historical current data for the circuit breaker, and (I2T)expected is the total expected future fault arc energy for all of the future arc events (N).
The (I2T)total is compared to an (I2T)limit which is specified as the trigger for the maintenance event, as represented by block 770. In one embodiment, (I2Tlimit is the circuit breaker manufacturer specified danger limit and the maintenance event is exceeding this danger limit, being within a given percentage of this danger limit, or some other suitable criteria. In one example, the danger limit is 27,000,000 Amp squared seconds. In one embodiment, (I2T)limit is the circuit breaker manufacturer specified warning limit and the maintenance event is exceeding this warning limit, being within a given percentage of this warning limit, or some other suitable criteria.
If (I2T)total is greater than (I2T)limit, as represented by block 772, time Ti is indicated as the future time corresponding to the maintenance event. Maintenance event forecasting software 732 may provide an indication of this time as mentioned herein in connection with block 708. If (I2T)total is not greater than (I2T)limit, maintenance event forecasting software 732 increments the time, as represented by block 774, and resets (I2T)expected to zero, as represented by block 776.
Maintenance event forecasting software 732 through processing sequence 760 may be used to forecast multiple types of scenarios of the timing of the future arc events.
In a first scenario, maintenance event forecasting software 732 may determine the time associated with a maintenance event that is caused by the next arc event. In this scenario, N is set equal to one and equation (1) may be expressed as equation 3:
(I2T)expected=(I2T)at time T
In a second scenario, maintenance event forecasting software 732 may determine the effect of a cluster of arcs (N) within a short period of time. Often times multiple arcs occur in a group, such as during a storm scenario. In one embodiment, maintenance event forecasting software 732 assumes that all of the arcs (N) happen at the same time Ti. In this scenario equation 1 may be expressed as equation 4:
(I2T)expected=N(I2T)at time T
This second scenario may be implemented to determine a likelihood of a maintenance event occurring during an approaching storm system. In one embodiment, historical data of the number of clustered arcs during storm activity, potentially as a function of wind speed, may be used to set a value for N.
In a third scenario, maintenance event forecasting software 732 may determine the effect of a plurality of arcs (N) occurring between the present time and time Ti at equally spaced intervals. In this scenario equation 1 may be expressed as equation 5:
Unlike the second scenario, in this scenario the (I2T) for each future arc event should be determined independently from look-up table 752. In one embodiment, the arcs are scheduled to occur randomly or at an unequal interval. In one embodiment, the time period may correspond to a pre-determined schedule for the breaker to open and close. In one example, the time periods may be of even duration. In one example, the time periods may be of uneven duration.
In a fourth scenario, maintenance event forecasting software 732 may determine the number arcs (N) within a specified period of time that may occur prior to a maintenance event occurring. Exemplary time periods include a portion of a day, a day, a week, and other suitable time periods. For a given time period (D), the number of arcs (N) may be expressed as equation 6:
In one embodiment, maintenance event forecasting software 732 determines the number of arcs (N) for multiple time periods and provides an indication of each N to the user. For each time period the (I2T)expected is based on the expected gas density. In one embodiment, maintenance event forecasting software 732 monitors multiple circuit breaker 102 and develops a maintenance schedule for the circuit breakers 102 based on the days that the N for each the respective circuit breakers falls below a given number.
In a fifth scenario, maintenance event forecasting software 732 may determine the number arcs (N) within a specified period of time that may occur prior to a maintenance event occurring. Exemplary time periods include a portion of a day, a day, a week, and other suitable time periods. For a given time period (D), the number of arcs (N) may be expressed as equation 7:
The (I2T)unexpected is based on a desired gas density. In this manner, an operator may be provided an indication of the number of arc events that circuit breaker 102 may experience if the gas density within enclosure 122 is increased to the desired gas density. The gas density may be increased to the desired gas density by refilling the gas level within enclosure 122.
In one embodiment, the controller 700 based on at least the at least gas characteristic determines the whether a future opening of circuit breaker 102 would provide a risk of failure of the circuit breaker 102, potentially resulting in damage to additional components in the proximity of circuit breaker 102. In one example, the risk of failure corresponds to the (I2T)total being above a threshold amount. If the opening of circuit breaker 102 would provide a risk of failure then controller 700 will not open circuit breaker 102, will provide a notification to a controller controlling circuit breaker 102 to not open circuit breaker 102, and/or will provide a notification to a remote controller to open another circuit breaker operatively coupled to circuit breaker 102 instead of circuit breaker 102. In one example, a statistically average fault arc energy is used by controller 700 for the determination. In one embodiment, controller 700 executes one of the above-mentioned scenarios to determine one of a number of arc events that may occur prior to circuit breaker 102 providing a risk of failure or a time which would relate to circuit breaker 102 providing a risk of failure.
In one embodiment, controller 700 operates a switch operatively coupled to the trip circuit of circuit breaker 102 to prevent the opening of circuit breaker 102. In one example, the switch is in series with a Solon switch which is also operatively coupled to the trip circuit.
Although (I2T) is discussed as the fault arc energy measure, IT may be used or another fault arc energy measure.
In one embodiment, monitoring system 100 monitors when a current passing through circuit breaker 102 exceeds a threshold amount and the length of time that the current is above this threshold. In one example, only the current passing through the breaker while the breaker is in a closed state is monitored relative to the threshold. This may be used as a measure of condition for other components used with monitoring system 100, such as transformers.
While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.
This application claims the benefit of U.S. Provisional Application Ser. No. 61/448,585, filed Mar. 2, 2011, titled GAS DENSITY MONITORING SYSTEM, the entire disclosure of which is expressly incorporated by reference herein.
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