WO2002091002A1 - Overhead line rating monitor - Google Patents
Overhead line rating monitor Download PDFInfo
- Publication number
- WO2002091002A1 WO2002091002A1 PCT/US2002/014048 US0214048W WO02091002A1 WO 2002091002 A1 WO2002091002 A1 WO 2002091002A1 US 0214048 W US0214048 W US 0214048W WO 02091002 A1 WO02091002 A1 WO 02091002A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- rod
- temperature
- hot
- cold
- hot rod
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/42—Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature
Definitions
- This invention relates, generally, to a device and method for determining thermal capacity of overhead power lines.
- Weather stations in the vicinity of the line can also be installed and used to provide data. However, most cannot provide accurate readings of wind that drops below two miles per hour. A typical rotating anemometer will stall at these levels, and the bearings in rotating anemometers tend to degrade, increasing their stall speed further and eventually requiring maintenance. Measurement of solar input and precipitation greatly increases the cost of the weather monitoring equipment.
- U.S. Patent No. 5,559,430 to Seppa discloses an apparatus that includes a replica of a portion of a power line. Thermocouples are included to measure the temperature of the replica and that of the ambient air. If full sun is assumed, this method allows for the calculation of an effective wind speed and rating. However, if the sun is partially hidden this estimation of the effective wind speed and rating is quite poor. Further, the apparatus is useless at night or other times when there is essentially no sunlight.
- the preferred embodiment of the invention is an apparatus designed to utilize the IEEE 738 equations.
- the preferred embodiment comprises two cylindrical rods of approximately the same diameter and material properties of the line to be rated.
- the rods are placed such that the effects of wind, sun, and precipitation on the apparatus mirror those affecting the line. This is most easily accomplished by elevating the apparatus on a pole, separating the rods with a crossarm so they do not shield one another from weather effects, and aligning the rods parallel to the line.
- Each of the rods has a thermocouple attached just under its surface near the longitudinal middle of the rod. The rods are of sufficient length so that the cooling out of the ends is insignificant compared to other effects.
- One of the rods has a resistive heater inserted into it designed to dissipate about the same amount of energy as the line operating at the static rating.
- a computer uses the thermocouple readings and attributes of the apparatus to calculate the thermal rating according to the IEEE 738 equations.
- Figure 1 is a top view of an embodiment of the invention.
- Figure 2 A is a side view of an embodiment of the invention.
- Figure 2B shows the preferred placement of the thermocouples.
- Figure 3 is an isometric view of the invention.
- Figure 4 is an exploded view of the invention.
- Figures 1 and 2 depict an embodiment of the invention.
- the line rating monitor is comprised of mast 4, cross arm 6, cold rod 2, and hot rod 3.
- the rods are elevated on mast 4 and separated with cross arm 6 to ensure they are not shielded from weather effects.
- the rods are oriented parallel to the power line being rated to ensure that the rods experience the same wind and solar effects as the line.
- the rods are made to have a similar diameter to the power line to be rated. This sizing makes application of the heat transfer equations more straightforward. Also, the rods should be constructed of a material with similar properties to the power line. Most power lines are constructed primarily of aluminum, making that the preferred material. However, numerous materials exist that are sufficiently similar. The surface of the rods should dulled with brushing and clear anodizing to make the radiative properties of the replica similar to that of the line.
- a heat source Housed within hot rod 3 is a heat source, preferably one or more resistance elements. Constant wattage heater cable can also be used.
- the heat source is chosen such that it can create a similar amount of heat per unit distance as the power line when the line is operating near its static rating.
- the power dissipated by the line due to resistive (I 2 R) losses is easy to estimate because the resistance of the line is known.
- the internal resistors are made to dissipate a variable amount of energy. Using a controller, the current to the resistors is altered such that the external temperature of hot rod 3 is approximately equal to the line's rating temperature. This will increase the accuracy of the monitor during high load conditions, when accuracy is most important. It will also increase the cost of the unit, however.
- Cold rod 2 has cold thermocouple 7 fixed to its surface near the longitudinal middle of the rod.
- hot rod 3 has hot thermocouple 8 fixed to it in the same manner.
- Cold thermocouple 7 measures the solar temperature, which corresponds to the no-current temperature of the line.
- Hot thermocouple 8 corresponds to what the temperature of the power line would be if the line were operating near its static rating.
- the effective wind speed is a theoretical measurement that combines the cooling effects of wind, moisture, and the like into an equivalent, single vector value for the wind speed. In this way, the difficulty of estimating the effects of precipitation and other moisture is eliminated.
- the algorithm below is quite effective. If the true direction of the wind is also desired, three pairs of rods can be set up oriented at 120 degrees to each other in the same plane. Each pair should have one hot rod and one cold rod. The three vector determinations of effective wind speed can be merged to determine the actual direction of the wind.
- R is the resistance of the conductor at its maximum allowable temperature (rating temperature).
- the current I is equal to the line rating if the conductor temperature within q c and q. is taken to be the rating temperature. Calculation of the line rating I is the ultimate object of the present invention.
- Equation 2a estimates the convective cooling at low wind speeds
- Equation 2b estimates convective cooling at high wind speeds
- Equation 2c estimates the natural convective cooling at times of no wind. Under any given set of conditions, the equation that yields the largest value should be used for q c . This will yield a conservative result for the overall convective cooling.
- the properties of air present in the equations should be taken at T fllm , equal to (T c +T a )/2.
- the invention calculates the line rating in the following way.
- Equation la every variable is known except for the wind direction and speed present in the q c + q. term.
- the q gen term is equal to the wattage of the heater and the q ⁇ term is set to zero.
- the heat input due to solar, ⁇ ⁇ can be assumed to be zero if all occurrences of the ambient temperature in the equations are replaced with the solar temperature, T s .
- the solar temperature is measured by cold thermocouple 7 on cold rod 2.
- the conductor temperature, T c is measured by hot thermocouple 8 on hot rod 3.
- Equation la yields the effective wind speed.
- the value represents the wind speed (perpendicular to the line) that would produce the same overall cooling effect as all effects present in the vicinity of the overhead line rating monitor. Then, substituting this value into Equation lb, the ampacity of the line under the current conditions is known.
- the above algorithm helps to smooth undue rating variation which might be due to such effects as gusts of wind or scattered clouds passing in front of the sun. If the wind gusted near the monitor, the temperature reading from hot thermocouple 8 would not immediately reflect this due to the time constant of the rod. Therefore the calculated rating would not increase greatly due to the brief local wind gust. This is desirable, since the line rating is really proportional to the average cooling effect along the line, and not just at the monitor location. Likewise, during low wind conditions, the wind speed and direction naturally tend to fluctuate more in time and distance (along the line). The time constant of the rod (which is made similar to the actual line) results in a natural averaging of the rating. Rapid fluctuations in the rating are unusable by operators due to their limited time and unpredictability.
- FIGS 1 and 3 show cold rod 2 and hot rod 3 separated by crossarm 6 and elevated on mast 4.
- Crossarm 6 is bolted at its center to mast clamp 5 and mast 4 with u-bolt 10.
- Crossarm 6 is preferably at least two feet long and constructed of aluminum. Near each end, two holes are made in crossarm 6 so that cold rod 2 and hot rod 3 can be inserted into crossarm 6 perpendicular to mast 4. Each hole on the side facing away from mast 4 is tapped for connection to the rods as discussed below.
- Junction box 17 is bolted to the underside of crossarm 6.
- Junction box 17 houses a terminal strip which provides a place to make power and thermocouple connections. In the likely event the monitor is on a roof or otherwise near a building, the connections for junction box 17 can run down the pole and into the building. If the monitor is at a remote location, junction box 17 can serve an additional purpose. It can house any necessary data acquisition device as well as radio or telephone equipment to transmit the data to the computer site.
- FIG 4 shows the preferred configuration of the aluminum rods.
- the rods should be constructed from thick-walled aluminum tubing. Tubing is chosen to provide the necessary cavity to house heater 13.
- the ends of the rods opposite crossarm 6 are sealed with rod plug 12, which should be made of Teflon and threaded to provide means of connecting rod plug 12 to the rods. Teflon provides a good thermal barrier and is resistant to both heat and UV rays.
- Heater 13 runs along the interior of hot rod 3.
- a power line running near its static rating dissipates between 15 and 30 watts of power per foot and this is the optimal power level for heater 13.
- Resistance heaters in general must be de-rated by fifty percent when running at the temperatures that will be present inside of hot rod 3. Therefore, it is recommended that heater 13 be rated for operation at 30 or 60 watts per foot.
- spacers can be used to center heater 13 inside of hot rod 3. However, because hot rod 3 has thick walls, the dissipation of heat will be fairly even without this component.
- Nipple 11 should be made of stainless steel pipe. Stainless steel provides the strength, corrosion resistance, and resistance to heat transfer required of the connector. Nipple 11 passes through crossarm 6 and out the other side. The side of nipple 11 that passes through crossarm 6 has an extended thread portion. These threads allow nipple 11 to be tightened onto crossarm 6 using brass cap 16 on the rear of crossarm 6 in combination with a nut on the front side. Hot rod 3 and cold rod 2, as shown in the Figure 4, screw onto the other end of nipple 11. As with the free end of the rods, nipple 11 is sealed with nipple plug 18, also made of Teflon. The outside of nipple 11 is covered with sleeve 14, preferably made of Teflon, to prevent radiation and convection of heat. This will help prevent nipple 11 from bleeding heat away from hot rod 3.
- Nipple 11 has a small hole in it near the end of the long threads that is within crossarm 6 after assembly. Wires from junction box 17 pass into crossarm 6 and into nipple 11 through this hole. Nipple plug 18 within nipple 11 has a hole drilled through its center through which the thermocouple and power wires then pass. The line supplying power to heater 13 simply connects to heater 13 at the point immediately inside of hot rod 3. The preferred configuration of thermocouple wire 18 is described below. All soldered connections inside of hot rod 3 should be made with high temperature solder. It is also desirable to have all wire inside hot rod 3 covered with ceramic braid to ensure proper resistance to heat.
- FIG 2A shows a side view of the invention including the position of hot thermocouple 8.
- Figure 2B is a detailed view showing how the thermocouple wire 19 exits hot rod 3 through a hole drilled through the tube wall.
- Thermocouple wire 19 is passed to the outside to prevent it from conducting the elevated temperatures present inside the tube to the thermocouple.
- the wire then travels for approximately one inch along the outside of hot rod 3 in a groove machined to a depth approximately equal to the diameter of the wire.
- the groove is filled with high temperature, UV resistant adhesive and smoothed over.
- Hot thermocouple 8 and cold thermocouple 7 are merely the stripped, twisted, and soldered ends of thermocouple wire 19.
- thermocouples are not absolutely required to practice the invention. Any means for measuring temperature known in the art will suffice. For example, thermistors, RTD's, or even an ordinary thermometer could be sufficient. There are of course other alternate embodiments that are obvious from the foregoing descriptions of the invention, which are intended to be included within the scope of the invention, as defined by the following claims.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NZ529683A NZ529683A (en) | 2001-05-03 | 2002-05-01 | Overhead line rating monitor |
AU2002303619A AU2002303619B2 (en) | 2001-05-03 | 2002-05-01 | Overhead line rating monitor |
AT02731649T ATE553389T1 (en) | 2001-05-03 | 2002-05-01 | NOMINAL VALUE MONITORING DEVICE FOR OVERLAND LINES |
EP02731649A EP1384084B1 (en) | 2001-05-03 | 2002-05-01 | Overhead line rating monitor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/848,738 US6441603B1 (en) | 2001-05-03 | 2001-05-03 | Overhead line rating monitor |
US09/848,738 | 2001-05-03 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002091002A1 true WO2002091002A1 (en) | 2002-11-14 |
WO2002091002A8 WO2002091002A8 (en) | 2003-04-10 |
Family
ID=25304137
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2002/014048 WO2002091002A1 (en) | 2001-05-03 | 2002-05-01 | Overhead line rating monitor |
Country Status (6)
Country | Link |
---|---|
US (1) | US6441603B1 (en) |
EP (1) | EP1384084B1 (en) |
AT (1) | ATE553389T1 (en) |
AU (1) | AU2002303619B2 (en) |
NZ (1) | NZ529683A (en) |
WO (1) | WO2002091002A1 (en) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102006024357A1 (en) * | 2006-05-18 | 2008-04-10 | Ldic Gmbh | Method and device for determining the electrical load capacity of overhead lines by means of temperature measurement |
US7620517B2 (en) * | 2007-02-05 | 2009-11-17 | Abb Research Ltd. | Real-time power-line sag monitoring using time-synchronized power system measurements |
US7494271B2 (en) * | 2007-02-05 | 2009-02-24 | Abb Research Ltd. | Power-line sag calculation by way of power-system state estimation |
US20090001811A1 (en) * | 2007-06-26 | 2009-01-01 | George Dewberry | Electrical line conditioner |
US20090001820A1 (en) * | 2007-06-26 | 2009-01-01 | George Dewberry | Electrical line conditioner |
CN102507044A (en) * | 2011-11-01 | 2012-06-20 | 国网电力科学研究院 | Multipoint temperature detection device for test of current-carrying capacity of cross-linked cables |
CN103576007B (en) * | 2012-07-19 | 2017-02-08 | 远东电缆有限公司 | Carbon fiber reinforced core overhead insulated cable current-carrying capacity heating test device and test method thereof |
CN102901897B (en) * | 2012-10-16 | 2015-11-18 | 浙江华电器材检测研究所 | Aerial condutor test method for energy consumption |
US20140163884A1 (en) | 2012-12-10 | 2014-06-12 | Universite De Liege | Method and system for the determination of wind speeds and incident radiation parameters of overhead power lines |
CA2829419C (en) | 2013-03-14 | 2020-06-02 | Hubbell Incorporated | Apparatuses, systems and methods for determining effective wind speed |
US20150194142A1 (en) * | 2014-01-03 | 2015-07-09 | Kevin Roberts | Device and method of use for a deer feeder sound enhancer |
FR3080199B1 (en) | 2018-04-13 | 2020-04-17 | Rte Reseau De Transport D'electricite | METHOD AND DEVICE FOR MEASURING AN EFFECTIVE WIND SPEED IN THE VICINITY OF AN OBJECT |
US20220112737A1 (en) * | 2020-10-10 | 2022-04-14 | James E. Morrison | Crossarm for an electrical pole |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4584523A (en) * | 1983-10-03 | 1986-04-22 | Rca Corporation | Measurement of the current flow in an electric power transmission line by detection of infrared radiation therefrom |
US5559430A (en) * | 1994-07-27 | 1996-09-24 | Seppa; Tapani O. | Net radiation sensor |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4268818A (en) | 1978-03-20 | 1981-05-19 | Murray W. Davis | Real-time parameter sensor-transmitter |
US4420752A (en) | 1978-03-20 | 1983-12-13 | Murray W. Davis | Real-time parameter sensor-transmitter |
US4553092A (en) | 1982-12-20 | 1985-11-12 | The Boeing Company | Apparatus and method for temperature estimation of overhead conductors |
US4689752A (en) | 1983-04-13 | 1987-08-25 | Niagara Mohawk Power Corporation | System and apparatus for monitoring and control of a bulk electric power delivery system |
US4728887A (en) * | 1984-06-22 | 1988-03-01 | Davis Murray W | System for rating electric power transmission lines and equipment |
US5341088A (en) | 1984-06-22 | 1994-08-23 | Davis Murray W | System for rating electric power transmission lines and equipment |
US5140257A (en) | 1984-06-22 | 1992-08-18 | Davis Murray W | System for rating electric power transmission lines and equipment |
US4806855A (en) | 1984-06-22 | 1989-02-21 | Davis Murray W | System for rating electric power transmission lines and equipment |
US5235861A (en) | 1991-05-03 | 1993-08-17 | Seppa Tapani O | Power transmission line monitoring system |
US5933355A (en) | 1995-05-04 | 1999-08-03 | Deb; Anjan Kumar | Object oriented expert power line ampacity system |
US6097298A (en) | 1998-02-13 | 2000-08-01 | Ecsi Corporation | Apparatus and method of monitoring a power transmission line |
-
2001
- 2001-05-03 US US09/848,738 patent/US6441603B1/en not_active Expired - Lifetime
-
2002
- 2002-05-01 WO PCT/US2002/014048 patent/WO2002091002A1/en not_active Application Discontinuation
- 2002-05-01 AT AT02731649T patent/ATE553389T1/en active
- 2002-05-01 NZ NZ529683A patent/NZ529683A/en not_active IP Right Cessation
- 2002-05-01 AU AU2002303619A patent/AU2002303619B2/en not_active Expired
- 2002-05-01 EP EP02731649A patent/EP1384084B1/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4584523A (en) * | 1983-10-03 | 1986-04-22 | Rca Corporation | Measurement of the current flow in an electric power transmission line by detection of infrared radiation therefrom |
US5559430A (en) * | 1994-07-27 | 1996-09-24 | Seppa; Tapani O. | Net radiation sensor |
Also Published As
Publication number | Publication date |
---|---|
EP1384084A4 (en) | 2010-02-03 |
US6441603B1 (en) | 2002-08-27 |
AU2002303619B2 (en) | 2006-06-01 |
ATE553389T1 (en) | 2012-04-15 |
WO2002091002A8 (en) | 2003-04-10 |
EP1384084A1 (en) | 2004-01-28 |
EP1384084B1 (en) | 2012-04-11 |
NZ529683A (en) | 2005-10-28 |
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