RU2287214C1 - Method for detecting ice and wind loads - Google Patents

Abstract

FIELD: power engineering; protection of power transmission lines against ice and wind loads.

SUBSTANCE: proposed method that involves use of transmitting and receiving equipment for measuring ice and wind loads on high-voltage power transmission lines includes recording of transmitting-equipment output resistance by means of transducer, for instance varistor, that varies in proportion to output voltage across magneto-elastic force sensor and, consequently, proportional to total ice load on ground wire; conversion of transmitting equipment output resistance as function of ice load into DC analog signal by means of signal processing device; conversion of DC analog signal into digital signal and its transfer to load dispatching center by means of telemechanical complex followed by its display at load-dispatching center by means of operating data complex.

EFFECT: enhanced reliability of measuring equipment and of data on ice loads transferred.

1 cl, 1 dwg

Description

The invention relates to the field of electric power and can be used to protect power lines from ice and wind loads.

A known method for the determination of ice loads, used for short-term forecasting of ice formation and control the installation of melting ice on an overhead power line. The method is based on an indirect measurement of the temperature linear expansion of the wire in the span between the tension and supporting insulator strings. Force sensors suspended between the support beam and a string of insulators measure the force of gravity, respectively, of the tension and supporting string of insulators. Using them, using a two-input linear converter, they form a signal proportional to the linear temperature expansion of the wire (RF Patent No. 2165122, IPC N 02 G 7/16, G 08 B 19/02, 04/10/2001).

The disadvantage of the prototype method is the inaccuracy of information about ice loads and the low reliability of measuring ice loads due to the fact that the method is based on indirect temperature measurement, and there is no information about the wind load.

A device for determining icing load on overhead power transmission lines, comprising a signaling device installed in an icing load monitoring station, including a signal transducer of an icing load sensor into an appropriate number-pulse code combination in the form of low-frequency pulses following in series in time, a cycle counter-shaper and a time counter-shaper delays associated with the comparator, a low-pass filter and a low-frequency pulse shaper, as well as reception block (RF Patent No. 2162268, IPC Н 02 G 7/16, G 08 В 19/02, 01/20/2001).

The disadvantage of the analogue is the dependence of the testimony on the load on the wire from interference, interference, currents spreading on the ground at the substation and high-voltage line, because a lightning protection cable is used as an information channel, and the earth is the common wire for such information transfer, which ultimately affects the reliability of information about ice loads on a high-voltage line and the reliability of measurements of ice loads.

It is also known a device for determining the maximum ice loads on the wires of power lines, including a sensing element installed in the housing, kinematically connected with the transducer of displacement into an electrical signal containing an encoder and a reader interacting with it. The sensing element is mounted on a knife support and is made in the form of a swinging beam, the smaller arm of which is connected to the controlled wire of the power line, and the larger arm is connected to the encoder of the converter through a mechanical discretizer, consisting of links located in the housing, providing conversion of fixed limit values of non-linearly varying ice loads in the linear movement of the encoder of the transducer with a given quantization step, and the control on, made in the form of a swinging lever mounted on the housing, the working arm of which is kinematically connected with the encoder of the transducer with the ability to move links that convert fixed fixed values of non-linearly varying ice loads into linear movement of the encoder of the transducer with a given quantization step, and to the other shoulder whose efforts are applied to the earth, simulating extreme ice loads, ensuring uninterrupted operation of the con trolled power line. The reader of the converter is made in the form of one or a group of sealed contacts that form the resulting digital signal at the output of the converter (RF Patent No. 2196378, IPC N 02 G 7/16, 01/10/2003).

The disadvantages of the analogue are the inaccuracy of information about ice loads on the high-voltage line and the low reliability of measurements of ice loads.

In addition, it is known a device for transmitting signals through a power line for detecting icy deposits on wires, comprising a transmission control unit made in the form of a high frequency generator coupled through an attachment filter and a coupling capacitor to a phase transmission wire, and a reception control unit comprising an alarm unit, connected through an attachment filter and a coupling capacitor to a phase transmission wire connected to measuring units connected to sensors of extreme glaze power line loads. The phase wire is used as a spatially distributed sensor of ice loads, to which the signals of the above high-frequency generators are transmitted as information carriers. The reception control units receive high-frequency signals from the specified spatially distributed icing load sensor, modulated by the icing load, which determines changes in icy deposits along the entire length of the transmission line. The values of the maximum ice loads at given points are determined by the maximum change in the same high-frequency signal, modulated by changing the parameters of one of the measuring units using the tuning regulator when the maximum ice load sensor is triggered. The outputs of the reception control units are connected to the controlled points of the telemechanics system, the signals from which are sent to the control room, which are used to judge the icing situation in the region (RF Patent No. 2209513, IPC Н 04 В 3/54, Н 02 J 13/00, Н 02 G 7/16, 07/27/2003).

The disadvantages of the analogue are the mandatory presence of a high-frequency channel with a frequency of no higher than 350 kHz and high-frequency signal processing, as well as the complexity and high cost of a signal transmission device.

The objective of the invention is to increase the reliability of equipment for measuring icy and wind loads by simplifying the design of the receiving apparatus of the device, as well as the reliability of transmitting information about icing loads on high voltage lines by measuring the output resistance of the transmitting equipment.

The problem is achieved by the method of determining ice and wind loads, by which the tensile forces of the lightning protection cable are first measured using magnetoelastic force sensors installed in the tension and supporting garlands of the insulators, they form a signal, in contrast to the prototype, the output resistance is recorded by means of a converter, for example a varistor , which varies in proportion to the output voltage of the magnetoelastic force sensor and, accordingly, in proportion to the total glaze load ke on a lightning protection cable, and the output resistance of the transmitting equipment, depending on the icy load, is converted into an analog DC signal using a signal processing device, then the analog DC signal is converted into a digital signal and transmitted to the control room via a telemechanical complex with subsequent output to the control room paragraph through the operational information complex.

The invention is illustrated in the drawing. The drawing shows a graph of the measurement of ice load and temperature versus time.

An example of a specific implementation of the method.

A magnetoelastic force sensor can be installed between the traverse and the ground wire insulator. The principle of operation of the magnetoelastic force sensor is based on the magnetoelastic effect, which consists in changing the magnetic properties of a ferromagnet under the influence of elastic mechanical stresses. The magnetoelastic force sensor consists of a magnetic circuit made of plates of electrotechnical cold-rolled steel. Two windings are applied to the magnetic circuit at an angle of 90 °. A power supply of 30 V is supplied to the primary winding of the magnetic circuit of the magnetoelastic force sensor; AC voltage is removed from the secondary winding.

The conversion of the 0-5 mA analog signal to a digital signal and its transmission to the control room is carried out using the Granite telemechanical complex.

Converting a digital signal into a convenient form (for example, in units of wire weight, kilograms) and outputting it to a dispatch center, for example, to a dispatcher’s personal computer monitor, is performed using the Dispatcher operational information complex.

The drawing shows as an example a graph of the change in ice load on the lightning protection cable of a high-voltage line depending on the change in the icing situation - the temperature obtained on the basis of the retrospective data of the operational information complex.

A retrospective of measurements of ice load and temperature is displayed on the graph with a quantization step of 30 minutes. The graph shows that under certain atmospheric conditions: air temperature from -4 ° to -10 ° and a certain humidity, ice formation is going on on the high-voltage line. When the weather changes: lowering air temperature, lowering humidity, the process of ice destruction on the high-voltage line is underway.

The reliability of the graph is confirmed by employees of the power line service, which conduct a visual inspection of the high-voltage line.

So, the claimed invention allows to obtain reliable information about ice loads on the high-voltage line and to increase the reliability of equipment for measuring ice and wind loads.

Claims (1)

A method for determining ice and wind loads, which measure the tensile forces of a lightning protection cable using magnetoelastic force sensors installed in the tension and support strings of insulators, which form a signal, characterized in that the output resistance of the transmitting equipment is first recorded by means of a converter, for example a varistor, which varies in proportion to the output voltage of the magnetoelastic force sensor and, accordingly, in proportion to the total glaze load on the storm cable, and the output resistance of the transmitting equipment, depending on the icy load, is converted into an analog DC signal by means of a signal processing device, then the analog DC signal is converted into a digital signal and transmitted to the control center by means of a telemechanical complex with subsequent output to the control center by means of operational information complex.