Patent Description:
Static line ratings set a static maximum level of current that should be applied to a transmission line, based on that line's clearance, to prevent the clearance from dropping below an acceptable level. To account for the fact that environmental variables impact the temperature of a transmission line, static line ratings may assume poor environmental conditions--for example, that the transmission line is in direct sunlight on a hot day with little wind. Many times, however, a transmission line may be experiencing more favorable environmental conditions. In these circumstances, the transmission line could safely carry more current than suggested by the static line rating. Other times, such as on an exceptionally hot day, the environmental conditions may be even worse than assumed by the static line rating. In these circumstances, a transmission line carrying a current within the static line rating may actually drop below an acceptable clearance level, creating an unsafe situation without exceeding the static line rating. In order to improve the efficiency of the distribution and consumption of electrical power, there is a need in the art for a dynamic or balanced system and method for adjusting an amount of current carried though a transmission line. As many electric utility operational decisions are made not in real-time bur rather in advance, there is a need to forecast what the rating will be in the future.

<CIT>, <CIT>, <CIT>, and <CIT> disclose related technologies.

Embodiments according to the present invention have been defined in the appended claims.

These and other features, aspects and advantages of the present invention will be more fully understood when considered with respect to the following detailed description, appended claims, and accompanying drawings.

The accompanying drawings, together with the specification, illustrate preferred and example embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention.

In the following detailed description, only certain preferred and example embodiments of the present invention are shown and described, by way of illustration. As those skilled in the art would recognize, the invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other example embodiments. Like reference numerals designate like elements throughout the specification.

In general terms, embodiments of the present disclosure are directed to a system and method for reliably anticipating what the current capacity of a transmission line will be during a given period in the future. The transmission line may have a minimum acceptable clearance. The clearance of the transmission line may depend on the temperature of the transmission line, and the temperature of the transmission line may depend on the current flowing in the transmission line. Accordingly, the transmission line's maximum capacity for carrying current may be defined in part by the minimum acceptable clearance of the transmission line.

A line operator may set the level of current flowing through a transmission line. At any given time, the maximum current that the transmission line can handle may depend on environmental conditions such as the ambient temperature at the transmission line, the wind on the transmission line, or the solar radiation on the transmission line, and therefore can change unpredictably. The system and method of the present disclosure may provide the operator with a reliability line rating. The reliability line rating identifies a current level that the operator may reliably apply to the transmission line without exceeding the instantaneous maximum line current, regardless of variations therein.

<FIG> is a schematic diagram showing a transmission line monitor <NUM> on a transmission line <NUM> according to embodiments of the present disclosure. The transmission line monitor <NUM> may be coupled to a transmission line <NUM> to gather information about the transmission line <NUM>. In some embodiments, the transmission line monitor <NUM> may be coupled to a critical span of the transmission line. A span is a length of the transmission line <NUM> extending between two attachment points, such as transmission line towers <NUM>. A span may be critical when it is expected that it might be the first span in the line to have a clearance violation when increasing operating current. This can be based on the height of the span (spans with lower clearance will have clearance violations earlier), the length of the span (longer spans lose more clearance for a given line temperature change), or the span's exposure to environmental variables (e.g. a span exposed to direct sunlight or that is protected from the wind will have a higher line temperature for a given current than a span that is protected from the sun or exposed to wind). In some embodiments, transmission line monitors <NUM> may be coupled to multiple spans in a transmission line, for example at multiple critical spans or at regular intervals along the transmission line.

<FIG> is a block diagram of a system <NUM> for determining a reliability current rating for a transmission line according to a preferred embodiment of the present disclosure. The preferred system <NUM> may include a transmission line monitor <NUM> and a reliability determination module <NUM> that is disposed on a remote utility server <NUM>. In alternative embodiments, the reliability determination module <NUM> can be integral with the transmission line monitor <NUM>. In still other alternative embodiments, the reliability determination module <NUM> can be a unitary module disposed on a single utility server <NUM>; multiple iterations or instantiations of a single module disposed on more than one utility server <NUM>; or at least partially disposed on a distinct server from the utility server <NUM>, such as for example on a cloud based system known to those of skill in the art of scalable computing.

Preferably, the transmission line monitor <NUM> may include a clearance sensor <NUM>. The clearance sensor <NUM> preferably functions to determine the present clearance of the span of the transmission line <NUM> and generate a line clearance measurement. In some embodiments, the clearance sensor <NUM> directly measures clearance d1 shown in <FIG>. For example, the transmission line monitor <NUM> and/or the clearance sensor <NUM> may be mounted on the transmission line <NUM> and may measure the distance between the clearance sensor <NUM> and the closest object below <NUM>. In some embodiments, the clearance sensor <NUM> can include a LIDAR subsystem to measure clearance between the clearance sensor <NUM> and the closest object below <NUM>. Alternatively, the clearance sensor <NUM> can include any other range finding system or subsystem, including sonar, radar, optical, image-based, or any suitable combination thereof. An example of a transmission line monitor including a clearance sensor is described in international patent application publication number <CIT>.

In other embodiments, the clearance sensor <NUM> may measure the sag d2 of the span of the transmission line, as shown in <FIG>, in lieu of or in addition to measuring the clearance d1. The sag d2 may be used to calculate the clearance d1 or may be used in place of or as a ratification of the measurement of the clearance d1. In other embodiments, the clearance sensor <NUM> may not be physically attached to the transmission line <NUM>, and may measure the sag and/or clearance of the transmission line <NUM> from a distance.

As shown in <FIG>, a preferred transmission line monitor <NUM> may also include a line temperature sensor <NUM>. The line temperature sensor <NUM> preferably functions to determine the present temperature of the transmission line <NUM> and generate a line temperature measurement. The line temperature sensor may directly measure the temperature of the transmission line <NUM>. In some embodiments, the line temperature sensor is a thermocouple. In other embodiments, the line temperature sensor is an infrared temperature measuring device.

In other embodiments, the line temperature sensor <NUM> may measure the current on the transmission line <NUM> and the environmental conditions that impact the temperature of the transmission line <NUM>, and the transmission line temperature may be calculated based these measurements, for example using IEEE Standard <NUM>. The calculation may be performed by the controller <NUM>, or the measurements may be transmitted to a utility server <NUM> and the calculation of the line temperature may be performed at the utility server <NUM> by the reliability determination module <NUM>. In other embodiments, the line temperature sensor <NUM> may measure the environmental conditions and/or other variables that impact the temperature of the transmission line <NUM> as the line temperature measurement instead of directly measuring or calculating the line temperature.

The preferred transmission line monitor <NUM> may also include one or more environmental condition sensors <NUM>. The environmental condition sensors <NUM> preferably function to measure conditions at the transmission line <NUM> that may impact the temperature of the transmission line other than the current flowing in the transmission line <NUM>. For example, the one or more environmental condition sensors <NUM> may include an ambient temperature (ground temperature) sensor.

As shown in <FIG>, the preferred transmission line monitor <NUM> may include a controller <NUM> and a communication circuit <NUM>. The controller <NUM> may be configured to receive the line clearance measurement and the line temperature measurement and communicate them to the communication circuit <NUM>. In some embodiments, the communication circuit <NUM> may receive the line clearance measurement and the line temperature measurement directly from the clearance sensor <NUM> and the line temperature sensor <NUM>, respectively, and the controller <NUM> may be omitted from the transmission line monitor <NUM>.

Preferably, the communication circuit <NUM> may include a transmitter and/or a receiver. The communication circuit <NUM> may transmit the line clearance measurement and the line temperature measurement to the utility server <NUM>. In some embodiments, the communication circuit <NUM> communicates with the utility server <NUM> through a network <NUM>. Various embodiments for the network <NUM> are possible. In some embodiments, the communication circuit <NUM> may initially communicate with a satellite or satellite network <NUM> as part of the network <NUM>. In other embodiments, the communication circuit <NUM> may initially communicate with a cellular telephone network as part of network <NUM>. In other embodiments shown in <FIG>, the communication circuit <NUM> may initially communicate wirelessly with a nearby receiver <NUM> that is coupled to network <NUM>. After the initial communication step, the network may be any number of communication networks that will be apparent to those of ordinary skill in the art. In some embodiments, the network <NUM> is a wide area network such as the Internet. In other alternative embodiments, the controller <NUM> and the communication circuit <NUM> can be integrated into a single component that provides on board data processing as well as communications thereof to at least the remote utility server <NUM>.

As shown in <FIG>, in an alternative preferred embodiment a first transmission line monitor <NUM> and a second transmission line monitor <NUM> are coupled to a transmission line <NUM> at different spans. The first transmission line monitor <NUM> may initially communicate with the second transmission line monitor <NUM>. The second transmission line monitor <NUM> may then communicate wirelessly with a nearby receiver <NUM> or may otherwise communicate through a network to a remote utility server <NUM>. In this manner, a number of transmission line monitors may communicate with one another to form a mesh network capable of connecting any transmission line monitor in the network to one or more utility servers <NUM> thereby extending the range over which the first transmission line monitor <NUM> may communicate with the receiver <NUM> and adding redundancy and reliability to the distribution system.

In another preferred embodiment of the system <NUM>, the reliability determination module <NUM> can generate a temperature-clearance model for the transmission line. For example, <FIG> is a graph depicting a notional temperature-clearance model <NUM> for a transmission line according to embodiments of the present disclosure.

A transmission line may lengthen with increased temperature. Accordingly, the clearance of a transmission line may depend on the temperature of the transmission line. The temperature-clearance model <NUM> may be a statistical model which can show or predict the clearance of the transmission line for a given line temperature. The temperature-clearance model <NUM> may be generated based on the clearance measurements and line temperature measurements <NUM> received from the transmission line monitor <NUM> over time. Clearance values may be compared to the line temperatures at which they were measured to determine the relationship between clearance and line temperature for the transmission line. By comparing multiple clearance values having multiple corresponding line temperatures, a best-fit statistical model (e.g., a linear model) may be determined. This best-fit statistical model may be used as the temperature-clearance model <NUM>. In some embodiments, the reliability determination module <NUM> may generate the temperature-clearance model <NUM> using linear regression. Linear regression may allow the temperature-clearance <NUM> model to accurately reflect transmission line behavior outside the ranges in that the clearance and line temperature were actually measured.

In some embodiments, the temperature-clearance model <NUM> may be regularly or continuously updated to be based on the most recent line temperature measurements and line clearance measurements <NUM>. The transmission line monitor <NUM> may gather a specified number of measurements <NUM> before the reliability determination module <NUM> generates the temperature-clearance model <NUM>. For example, the temperature-clearance model <NUM> may be generated every <NUM> hours based on the measurements <NUM> gathered during the previous <NUM> hours. In other embodiments, the interval between updates of the temperature-clearance model <NUM> can be variable, manual, seasonal, or continuously with streaming and/or near real time temperature information being received at the reliability determination module <NUM>.

In some embodiments, the temperature-clearance model <NUM> may be a statistical model which can show or predict the clearance of the transmission line for a given set of environmental variables. For example, the temperature-clearance model <NUM> may directly model the relationship between environmental conditions impacting line temperature and the clearance of the transmission line.

In some embodiments, the temperature-clearance model <NUM> may use a back-calculated effective-ambient temperature in modeling the relationship between line temperature and clearance. Instead of using a direct ambient temperature measurement, the transmission line monitor <NUM> or the reliability determination module <NUM> may utilize an equation for calculating transmission line temperature which includes ambient temperature as a variable (e.g. IEEE Standard <NUM>). It may receive values or measurements for all of the other variables in the equation, and calculate the ambient temperature based on those values, utilizing the calculated value as the effective-ambient temperature. The effective-ambient temperature may then be used in generating the temperature-clearance model <NUM>.

In some preferred embodiments, the reliability determination module <NUM> monitors the temperature-clearance model <NUM> for changes. For example, the reliability determination module <NUM> may record and monitor the Y-intercept of the temperature-clearance model <NUM> for changes. In other embodiments, the reliability determination module <NUM> may record and monitor the slope of the temperature-clearance model <NUM>. Because the temperature-clearance model <NUM> is an approximation or extrapolation based on a limited set of data, a degree of variation may be expected. Significant changes, outside the expected degree of variation, may indicate that something in the environment of the transmission line has changed. For example, a significant change in the temperature-clearance model <NUM> may indicate that a change in the environment beneath the transmission line (foliage growths out to be beneath transmission line, large object placed beneath line), or that the transmission line conductor properties have changed due to a heavy mechanical load (ice) or due to overheating. In some embodiments, the reliability determination module <NUM> may alert an operator when significant changes in the temperature-clearance model <NUM> are detected.

In normal operation of the preferred system <NUM>, the transmission line <NUM> may have a minimum acceptable clearance <NUM>. The minimum acceptable clearance <NUM> for the transmission line <NUM> may be compared to the temperature-clearance model <NUM> for the transmission line <NUM> to find a maximum allowable line temperature <NUM> for the transmission line <NUM>, at which the transmission line <NUM> will no longer meet the minimum acceptable clearance <NUM>. The line temperature of the transmission line <NUM> may depend on the current in the transmission line <NUM> and environmental conditions at the transmission line such as the ambient temperature at the transmission line <NUM>, the wind on the transmission line <NUM>, or the solar radiation on the transmission line <NUM>.

A dynamic line rating (hereinafter 'DLR') for a transmission line <NUM>, at a given moment, may be the amount of current that an operator may run through a transmission line <NUM> at that moment without exceeding the maximum line temperature <NUM> for the transmission line <NUM>. Because the line temperature is based on both current and environmental conditions, the DLR of a transmission line <NUM> can vary over time based on changes in environmental conditions. A discussion of calculating the DLR of a transmission line can be found in <CIT>.

<FIG> is a diagram showing line ratings over time, including a reliability line rating <NUM> for a present interval <NUM>.

The initial DLR for an interval may be the DLR at the beginning of the interval. Accordingly, the initial dynamic line rating <NUM> for the present interval <NUM> may be the dynamic line rating at the present time <NUM>.

As used herein, an interval may be a period of time of a particular duration. Time may be represented as a series of consecutive intervals. In some embodiments, each interval may be one hour long. The present interval <NUM> may be the interval beginning at the present time <NUM>.

As discussed above, a transmission line <NUM> may have an instantaneous maximum current (or DLR) that varies over time. The reliability line rating <NUM> for the present interval <NUM> may be a level of current that the transmission line <NUM> may reliably carry for the duration of the present interval <NUM> without exceeding the DLR, regardless of variations therein (and/or without dropping below the minimum acceptable clearance or exceeding the conductor maximum line temperature).

Preferably, a DLR record <NUM> may be a set of values that are related to or based on past values of the transmission line DLR. In some alternative embodiments, the DLR record <NUM> may simply be the past plurality of DLR values <NUM>. In other alternative embodiments, the DLR record <NUM> may include error level values <NUM>. An error level may correspond to a past interval during which the DLR was generated at multiple times, including at the beginning of the interval ("the initial DLR"). The error level may be a value which represents and/or is based on the difference between the initial DLR and the DLRs generated during the past interval.

<FIG> is a flow chart showing a method <NUM> for generating a reliability line rating <NUM> for a present interval <NUM> according to a preferred embodiment of the present disclosure. Referring to <FIG>, at block <NUM>, the reliability determination module <NUM> preferably receives line clearance measurements and corresponding line temperature measurements for an interval. The line clearance measurements and the line temperature measurements may be received from a transmission line monitor <NUM>. At block <NUM>, the reliability determination module <NUM> preferably generates a temperature-clearance model for a transmission line. The temperature-clearance model may be generated based on past line clearance measurements and line temperature measurements. In some embodiments, the temperature-clearance model is generated as described above in reference to <FIG>.

At block <NUM>, the reliability determination module <NUM> preferably generates a plurality of DLRs over time. In some alternative embodiments, the dynamic line ratings may be based on the temperature-clearance model. The generated dynamic line ratings may be a plurality of past dynamic line ratings <NUM>. In generating a DLR, the utility server <NUM> may receive environmental condition measurements. In other alternative embodiments, these measurements may be gathered by the transmission line monitor <NUM> and transmitted to the reliability determination module <NUM>. In other embodiments, these measurements are gathered by remote sensors not coupled to the transmission line monitor <NUM>. For example, the remote sensors may be located at a transmission line tower or at a power substation. In other embodiments, the environmental condition measurements are received from third-party services that record and/or forecast environmental conditions on a large scale, such as the National Oceanic and Atmospheric Administration (NOAA) or a forecast aggregating service.

Once the environmental conditions at the transmission line are known, the reliability determination module <NUM> preferably determines what level of current would result in the transmission line reaching the maximum line temperature; this level of current may be the DLR of the transmission line at that time. In some embodiments, the utility server may make this determination by putting the environmental condition measurements into a formula for transmission line temperature, and solving for the current level. In some embodiments, the formula is IEEE Standard <NUM>.

In other alternative embodiments, the reliability determination module <NUM> determines the DLR using a model generated based on past values of the environmental condition measurements and line temperature measurements. The reliability determination module <NUM> preferably generates a model that models the relationship between transmission line temperature and the environmental conditions. In some embodiments, this model may be generated using machine learning techniques. The reliability determination module <NUM> preferably uses the model to determine the level of current that would result in the maximum transmission line temperature, given the currently measured environmental conditions. In other alternative embodiments, a transmission line monitor <NUM> may calculate the DLR for the transmission line and a reliability determination module <NUM> may receive the DLR from the transmission line monitor <NUM>. For example, a controller <NUM> may calculate the DLR, and the communication circuit <NUM> may transmit the DLR to the reliability determination module <NUM>.

At block <NUM>, the reliability determination module <NUM> preferably generates a DLR record <NUM>. The DLR record values may be based on the plurality of past DLR values <NUM> generated at block <NUM>. In some embodiments, the DLR record <NUM> may simply be the plurality of past DLR values <NUM> generated at block <NUM>. In other alternative embodiments, the DLR record values may be error levels <NUM>. In some embodiments, the error level <NUM> for an interval may be the difference between the initial DLR and the average value of the DLRs generated during the interval. In other embodiments, the error level for an interval may be the difference between the initial DLR and the lowest DLR generated during the interval.

At block <NUM>, the reliability determination module <NUM> preferably determines a scaling factor based on the DLR record <NUM> and a confidence level. The confidence level may be a percentage. In some embodiments, the scaling factor may be a constant with a value less than <NUM> which, when multiplied by the mean value for the DLR record values, results in a cutoff value that a percentage of DLR record values equal to the confidence level will be above. For example, a confidence level may be <NUM>%. The cutoff value will be the value of the second percentile of the DLR record values--a value that <NUM>% of the DLR record values will be above. The scaling factor will be a constant which, when multiplied by the mean of the DLR record values, equals the cutoff value.

In some alternative embodiments, the scaling factor may be generated based on all past DLR record values for the transmission line. In other embodiments, the scaling factor may be generated based on the DLR record values from a past time window. For example, the scaling factor may be generated based on the DLR record values recorded in the last <NUM> hours. In other alternative embodiments, the scaling factor may be generated based on DLR record values from a first past time window <NUM> and a second past time window <NUM> including different times. In some embodiments, the time windows <NUM> and <NUM> may be different lengths. In some embodiments, the time windows <NUM> and <NUM> may overlap. For example, the first time window <NUM> can be the last <NUM> hours, and the second time window <NUM> can be the last <NUM> hours. A first intermediate scaling factor may be generated for the first past time window <NUM> based on the DLR record values in the first window <NUM>, and a second intermediate scaling factor may be generated for the second past time window <NUM> based on the DLR record values in the second window <NUM>. The first intermediate scaling factor and the second intermediate scaling factor may be averaged to generate the scaling factor. In some embodiments, the first intermediate scaling factor and the second intermediate scaling factor may be given different weights in creating the scaling factor. The weights may vary based on prevailing circumstances; for example, a more recent time window may be given a higher weight when a storm is forecasted, thereby giving greater weight to recent DLR record values, causing the scaling factor to adjust to changing circumstances after a shorter delay.

At block <NUM>, the reliability determination module <NUM> preferably generates an initial DLR <NUM> for the present interval <NUM>. The initial DLR <NUM> for the present interval <NUM> may be generated as described above in reference to block <NUM>. In other embodiments, the initial DLR <NUM> for the present interval <NUM> may be generated by the transmission line monitor <NUM> and transmitted to the utility server <NUM>.

At block <NUM>, the reliability determination module <NUM> preferably scales the initial DLR <NUM> for the present interval <NUM> down based on the scaling factor determined at block <NUM>. For example, the initial DLR <NUM> for the present interval <NUM> may be multiplied by the scaling factor. The resulting value may be the reliability line rating <NUM> for the transmission line for the present interval <NUM>. The reliability determination module <NUM> may communicate the reliability line rating <NUM> to a transmission line operator, for example through a display coupled to the reliability determination module <NUM>, so that the transmission line operator may utilize the reliability line rating <NUM> in setting the level of current on the transmission line. In some embodiments, the utility server <NUM> is coupled to the system controlling the level of current on the transmission line, such as an energy management system, and the reliability determination module <NUM> limits the level of current that the system can apply based on the reliability line rating <NUM>. In some embodiments, the reliability determination module <NUM> may determine reliability line ratings for multiple spans on a single transmission line. It may then determine the lowest of the reliability line ratings for the various spans and utilize it as the reliability line rating for the entire transmission line. The reliability determination module <NUM> may display the reliability line rating for the entire transmission line to a transmission line operator, or may limit the level of current on the transmission line (for example through an energy management system) based on the reliability line rating for the entire transmission line.

The description above of the method <NUM> depicted in <FIG> includes references to the system of <FIG>. In some embodiments, the method <NUM> of <FIG> is performed by the reliability determination module <NUM> of <FIG>. However, in other embodiments, the method <NUM> of <FIG>, as described above, is not performed by the system of <FIG>, and accordingly the disclosure above should not be limited thereto.

<FIG> is a diagram showing line ratings over time, including a reliability line rating <NUM> for a future time window <NUM>.

A reliability line rating <NUM> for a future time window <NUM> may be a level of current that the transmission line may reliably carry for the duration of the future time window <NUM> without exceeding the DLR, regardless of variations therein (and/or without dropping below the minimum acceptable clearance or exceeding the maximum line temperature). A reliability line rating <NUM> for a future time window <NUM> may be based on a forecasted DLR <NUM> (hereinafter "FDLR") for a future interval <NUM>. A future interval <NUM> may be a period of time occurring a set amount of time from the present time <NUM>. The future interval <NUM> may be within the future time window <NUM>. A FDLR <NUM> for a future interval <NUM> may be what the DLR of the transmission line would be if the environmental conditions at the transmission line were the environmental conditions forecasted for the future interval <NUM>. For example, FDLR(<NUM>) may represent FDLRs <NUM> generated based on forecasts of environmental conditions <NUM> hours from the time of forecasting (i.e. present time <NUM>).

Error level values <NUM> may correspond to past FDLRs <NUM> for the interval <NUM> (e.g. past FDLRs <NUM> generated based on forecasts the same amount of time in the future). An error level may be a value that represents and/or is based on the difference between the generated FDLR <NUM> and the actual DLR as generated at the corresponding later time.

<FIG> is a flow chart showing a method <NUM> for generating a reliability rating for a future time window according to another preferred embodiment of the present disclosure.

Block <NUM> recites the reliability determination module <NUM> preferably generates a temperature-clearance model. The reliability determination module <NUM> may receive a line clearance measurement and a line temperature measurement for an interval. The line clearance measurement and the line temperature measurement may be received from a transmission line monitor <NUM>. The temperature-clearance model may be generated based on past line clearance measurements and line temperature measurements. In some embodiments, the temperature-clearance model is generated as described above in reference to <FIG>.

As shown in <FIG>, block <NUM> recites that the reliability determination module <NUM> may generate a plurality of past DLR ratings. The reliability determination module <NUM> may generate a plurality of DLRs over time. In some embodiments, the DLRs may be based on the temperature-clearance model generated at block <NUM>. In generating a DLR, the reliability determination module <NUM> may receive environmental condition measurements. In some embodiments, these measurements may be gathered by the transmission line monitor <NUM> and transmitted to the reliability determination module <NUM>. In other embodiments, these measurements are gathered by remote sensors not coupled to the transmission line monitor <NUM>. For example, the remote sensors may be located at a transmission line tower or at a power substation. In other embodiments, the environmental condition measurements are received from third-party services that record and/or forecast environmental conditions on a large scale, such as NOAA.

Once the environmental conditions at the transmission line are known, the reliability determination module <NUM> may determine what level of current would result in the transmission line reaching the maximum line temperature; this level of current may be the DLR of the transmission line at that time. In some embodiments, the utility server may make this determination by putting the environmental condition measurements into a formula for transmission line temperature, and solving for the current level. In some embodiments, the formula is IEEE Standard <NUM>.

In other embodiments, the reliability determination module <NUM> determines the DLR using a model generated based on past values of the environmental condition measurements and line temperature measurements. The reliability determination module <NUM> preferably generates a model that models the relationship between transmission line temperature and the environmental conditions. In some embodiments, this model may be generated using machine learning techniques. The reliability determination module <NUM> may use the model to determine the level of current that would result in the maximum transmission line temperature, given the currently measured environmental conditions.

In other embodiments, a transmission line monitor <NUM> may calculate the DLR for the transmission line and a reliability determination module <NUM> may receive the DLR from the transmission line monitor <NUM>. For example, a controller <NUM> may calculate the DLR, and the communication circuit <NUM> may transmit the DLR to the reliability determination module <NUM>.

As shown in <FIG> block <NUM> recites that the reliability determination module <NUM> preferably receives forecasted environmental conditions for the future interval <NUM>. The forecasted measurements may be received from a third-party service that records and forecasts environmental conditions on a large scale, such as NOAA, or a forecast aggregating service. Alternatively, the forecasted measurements may be generated based on measurements received from forecasting equipment such as a barometer.

As shown in <FIG>, block <NUM> recites that the reliability determination module <NUM> preferably generates a plurality of past FDLRs corresponding to the future interval <NUM>. For example, the utility server <NUM> may generate a plurality of FDLRs generated in the past based on environmental conditions forecasted <NUM> hours out. The reliability determination module <NUM> may generate a FDLR by putting the forecasted values of the environmental conditions into a formula for transmission line temperature, and solving for the current level. In some embodiments, the formula may be IEEE Standard <NUM>.

In other alternative embodiments, the reliability determination module <NUM> generates the FDLR by comparing the forecasted environmental conditions to a model generated based on past values of the environmental condition measurements and line temperature measurements. The reliability determination module <NUM> may generate a model that models the relationship between transmission line temperature and the environmental conditions. In some embodiments, this model may be generated using machine learning techniques. The reliability determination module <NUM> may use the model to generate the FDLR by determining the level of current that would result in the maximum transmission line temperature, given the forecasted values of the environmental conditions.

As shown in <FIG>, block <NUM> recites that the reliability determination module <NUM> preferably generates one or more error level values <NUM> corresponding to past FDLRs for the future interval <NUM>. The error level values <NUM> may be generated based on the plurality of past FDLRs and the plurality of past DLRs. The error level value <NUM> for a given past FDLR may be the difference between the past FDLR and the average value of the actual DLRs generated at the corresponding time. In other embodiments, the error level value <NUM> for a past FDLR may be the difference between the past FDLR and the lowest actual DLR generated at the corresponding time.

As shown in <FIG>, block 612recites that the reliability determination module <NUM> preferably generates a FDLR <NUM> for the future interval <NUM>. The forecasted FDLR <NUM> for the future interval <NUM> may be generated by putting the values of the environmental conditions forecasted at the future interval <NUM> into a formula for transmission line temperature, and solving for the current level. In some embodiments, the formula may be IEEE Standard <NUM>. In other alternative embodiments, the FDLR <NUM> for the future interval <NUM> may be generated by comparing the values of the environmental conditions forecasted at the future interval <NUM> to a model generated based on past values of the environmental condition measurements and line temperature measurements. The reliability determination module <NUM> may generate a model that models the relationship between transmission line temperature and the environmental conditions. In some embodiments, this model may be generated using machine learning techniques. The reliability determination module <NUM> may use the model to generate the FDLR by determining the level of current that would result in the maximum transmission line temperature, given the forecasted values of the environmental conditions.

As shown in <FIG>, block <NUM> recites that the reliability determination module <NUM> preferably scales the FDLR <NUM> for the future interval <NUM> down. The reliability determination module <NUM> may determine a scaling factor based on the error level values <NUM> and a confidence level. The confidence level may be a percentage. In some alternative embodiments, the scaling factor may be a constant with a value less than <NUM> which, when multiplied by the mean value of the error level values <NUM>, results in a cutoff value that a percentage of error level values <NUM> equal to the confidence level will be above. For example, a confidence level may be <NUM>%. The cutoff value will be the value of the second percentile of the error level values <NUM>--a value that <NUM>% of the error level values <NUM> will be above. The scaling factor will be a constant that, when multiplied by the mean of the error level values <NUM>, equals the cutoff value. The reliability determination module <NUM> preferably scales the FDLR <NUM> for the future interval <NUM> down based on the scaling factor. For example, the FDLR <NUM> for the future interval <NUM> may be multiplied by the scaling factor. The resulting value may be the reliability line rating for the transmission line for the future interval <NUM>.

As shown in <FIG>, block <NUM> recites that the reliability determination module <NUM> may determine the reliability line rating <NUM> for the future time window <NUM>. The reliability line rating <NUM> for the future time window <NUM> may be based on the reliability line rating for the future interval <NUM>. The reliability determination module <NUM> may communicate the reliability line rating <NUM> for the future time window <NUM> to a transmission line operator, for example through a display coupled to the reliability determination module <NUM>, so that the transmission line operator may utilize the reliability line rating <NUM> for the future time window <NUM> in setting the level of current on the transmission line or planning for future levels to meet anticipated power needs. In some alternative embodiments, the reliability line rating <NUM> for the future time window <NUM> is determined to be the reliability line rating for the future interval <NUM>. In other alternative embodiments, the reliability line rating <NUM> for the future time window <NUM> is determined based on a plurality of reliability line ratings corresponding to a plurality of future time intervals. For example, <FIG> is a diagram showing a plurality of reliability line ratings RLR1-RLR7 for a plurality of future intervals I1-I7 according to embodiments of the present disclosure. The future time window 628C is divided into consecutive intervals I1-I7. Each of the consecutive intervals I1-I7 has a corresponding forecasted dynamic line rating FDLR1-FDLR7 generated as described in block <NUM>.

Based on the forecasted dynamic line ratings FDLR1-FDLR7, each of the consecutive intervals I1-I7 has a corresponding reliability line rating RLR1-RLR7 generated as described in the preferred method described in blocks <NUM>-<NUM>. At block <NUM>, the reliability determination module <NUM> preferably selects the lowest of the plurality of reliability line ratings RLR1-RLR7 for the consecutive intervals <NUM>-<NUM> to be the reliability line rating for the future time window to be the reliability line rating 650C for the future window 628C.

The scaling factor generated for a consecutive interval <NUM>-<NUM> forecasted further out may be lower than a scaling factor for a consecutive interval forecasted closer to the present time. For example, the scaling factor for FDLR7 may be lower than the scaling factor for FDLR3. This may be because forecasted environmental conditions may be more accurate closer to the present time. However, sometimes the scaling factor may be similar across each of the consecutive intervals <NUM>-<NUM>. This may occur, for example, where the weather has been stable and can be forecasted reliably.

The description above of the preferred method <NUM> depicted in <FIG> includes references to the system of <FIG>. In some embodiments, the method <NUM> of <FIG> is performed by the reliability determination module <NUM> of <FIG>. However, in other embodiments, the method <NUM> of <FIG>, as described above, is not performed by the system of <FIG>, and accordingly the disclosure above should not be limited thereto.

<FIG> shows a graph <NUM> depicting reliability line rating traces according to some embodiments of the present disclosure. The graph may have a time axis and a current axis. The graph may include various traces such as a dynamic line rating trace <NUM>, a reliability line rating trace <NUM>, a reliability window trace <NUM>, a static line rating trace <NUM>, or an actual load trace <NUM>. The traces may be for a transmission line or for a particular span of a transmission line. In some embodiments, the reliability determination module <NUM> may be coupled to a display and the reliability determination module <NUM> may cause the display to output a graph including one or more of the above traces, or multiples thereof.

Static line ratings, dynamic line ratings and reliability line ratings may measure "ampacity" which is a maximum current capacity for the transmission line. Accordingly, these measurements may be positioned relative to the current axis.

The dynamic line rating trace <NUM> may show values of the dynamic line rating calculated at different times. A dynamic line rating value for a transmission line changes over time, so the dynamic line rating values may be positioned relative to the time axis. The dynamic line rating trace <NUM> may, therefore, show dynamic line rating values generated over time and the times for which they were gathered.

The reliability line rating trace <NUM> may show values of a reliability line rating calculated for different times. Reliability line rating values, when generated (e.g. at a present time), may correspond to a future time. For example, the reliability line rating <NUM> of <FIG> is a reliability line rating for a present interval; the future time may be the time at the end of the present interval. As another example, the reliability line rating <NUM> of <FIG> is a reliability line rating for a future interval; the future time may be a time during the future interval, such as the beginning or the end of the future interval. The reliability line rating trace <NUM> may show the reliability line rating values positioned relative to the time axis based on their corresponding future times--that is, they may be positioned at the future time, not the time they are calculated. Accordingly, at a given present time, the reliability line rating trace <NUM> may display values at points on the time axis which are in the future.

The reliability window trace <NUM> may show values of a reliability line rating calculated for time windows. For example, the reliability line rating 650C of <FIG> is a reliability line rating for the time window 628C. The reliability window trace <NUM> may show the reliability line rating value for a window positioned at all of the points on the time axis included in the window. It may also include consecutive time windows and reliability line rating values for each consecutive time window, and accordingly may display a series of time windows with a single value for each window. For example, in one embodiment, time is divided into a series of one-day-long time windows, and the reliability window trace <NUM> may display a single reliability line rating for each day. Because reliability line ratings for time windows may be generated for future time windows, the reliability window trace <NUM> may also display values at points on the time axis in the future.

The static line rating trace <NUM> may simply show the static line rating for the transmission line at a given time. Accordingly, this trace may display a constant value, or an infrequently changing value. The actual load trace <NUM> may show the actual current load that was on the transmission line at a given time.

In one embodiment, the graph includes a first trace which is a reliability window trace <NUM>, a second trace which may be a reliability line rating trace <NUM> or another reliability window trace, and a dynamic line rating trace. The first trace may be to show longer-term reliability, and the second trace may be to show short term (e.g. emergency) reliability. For example, the first trace may display reliability line rating values for one-day windows. A utility may use this trace for planning purposes. The second trace may display reliability line ratings for short windows, such as a one or two hour window, or may display continuously generated reliability line rating values for one or two hours in the future. A utility may use this trace to anticipate or identify emergency situations, such as where the reliability line rating may drop below the actual load in the near future without action from the utility.

In some embodiments, the display may be part of a user interface (e.g. a graphical user interface). The user interface may be coupled to an energy management system or another system controlling the current on the transmission line. A user may be able to select a point on the graph. The user interface will communicate the current level associated with the selected point to the energy management system or other system which will use (or attempt to use) that current level as the current load for the transmission line. As the user may make the selection on the same graph as the traces, the user may use the information they contain in making his or her decision. The user may user the future values of a reliability line rating trace <NUM> and/or a reliability window trace <NUM> to determine what level he or she can reliably select, and may use their historical values compared to other traces (such as a dynamic line rating trace <NUM>, a static line rating trace <NUM>, and an actual load trace <NUM>) to determine what level of confidence he or she should attribute to the reliability line rating trace <NUM> and/or reliability window trace <NUM>.

It will be understood that, although the terms "first," "second," "third," etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. Thus, a first element, component, region, layer or section described below could be termed a second element, component, region, layer or section.

It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. In addition, it will also be understood that when an element or layer is referred to as being "between" two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the present invention. It will be further understood that the terms "comprises," "comprising," "includes," and "including," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

As used herein, the term "substantially," "about," and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art. Further, the use of "may" when describing embodiments of the present invention refers to "one or more embodiments of the present invention. " As used herein, the terms "use," "using," and "used" may be considered synonymous with the terms "utilize," "utilizing," and "utilized," respectively.

The electronic or electric devices and/or any other relevant devices or components according to embodiments of the present invention described herein may be implemented utilizing any suitable hardware, firmware (e.g. an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices may be formed on one integrated circuit (IC) chip or on separate IC chips. Further, the various components of these devices may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on one substrate. Further, the various components of these devices may be a process or thread, running on one or more processors, in one or more computing devices, executing computer program instructions and interacting with other system components for performing the various functionalities described herein. The computer program instructions are stored in a memory that may be implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer readable media such as, for example, a CD-ROM, flash drive, or the like. Also, a person of skill in the art should recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices.

Claim 1:
A system (<NUM>) for determining a reliability line rating (<NUM>) for a transmission line (<NUM>) during a present interval (<NUM>), the system comprising:
a reliability determination module (<NUM>); and
a line monitor (<NUM>) on a transmission line, the line monitor comprising:
a clearance sensor (<NUM>) to determine a line clearance measurement;
a line temperature sensor (<NUM>) to determine a line temperature measurement; and
a transmitter (<NUM>) to transmit the line clearance measurement and the line temperature measurement (<NUM>) to the reliability determination module (<NUM>) disposed on a remote utility server (<NUM>), the reliability determination module being configured to, in response to the line clearance measurement and the line temperature measurement, generate a temperature-clearance model (<NUM>) for the transmission line based on the received line clearance measurement and line temperature measurement,
characterized in that the line monitor further comprises a line current sensor to determine a line electrical load, and in that the reliability determination module is further configured to:
generate a plurality of past dynamic line ratings (<NUM>) based on a maximum line temperature (<NUM>) for the transmission line, wherein the maximum line temperature is determined by comparing a minimum acceptable clearance (<NUM>) for the transmission line to the temperature-clearance model;
determine a scaling factor based on the plurality of past dynamic line ratings;
generate a present dynamic line rating at a start of a present interval; and
scale the present dynamic line rating in response to the scaling factor to obtain a reliability line rating for the present interval.