RU2680160C2 - Method of diagnostics and monitoring of coupling capacitors technical condition under working voltage - Google Patents

Abstract

FIELD: electric power engineering.SUBSTANCE: claimed invention relates to electric power industry, namely to the issues of diagnostics and monitoring of electrical equipment, allowing to monitor the technical condition of communication capacitors of a voltage class of 110–500 kV. Method of diagnostics and monitoring the technical condition of communication capacitors under operating voltage includes determining the capacitance value of a communication capacitor before bringing into operation, measurement of capacitive current flowing through a communication capacitor under an operating voltage, and operating voltage of the network in real time mode. Next, the capacitance of the communication capacitor is calculated from the measured values ​​of current and voltage, the comparison of the obtained capacitance value with the capacitance value of the communication capacitor, diagnostics and monitoring of the technical condition of an object is determined before bringing into operation, and the capacitance value is calculated and compared constantly in real time mode so that the high-frequency communication channel is in operation during the measurement. It will also avoid or prevent in time emergency situations (accidents) that may arise as a result of failure of a communication capacitor.EFFECT: technical result consists in the possibility of obtaining reliable information about the technical condition of a communication capacitor in real time mode, thereby increasing the reliability of the networks of controlled facilities where they are installed.1 cl, 14 dwg, 1 tbl

Description

The claimed invention relates to the field of electric power, namely, to issues of diagnostics and monitoring of electrical equipment, allowing to control the technical condition of communication capacitors of voltage class 110-500 kV.

Communication and power take-off capacitors are used at substations in measuring devices, in special power take-off devices from power lines, as well as for the formation of high-frequency (HF) protection channels, telemechanics and telephone communications according to the power-to-ground wire circuit.

The use of high voltage lines for the simultaneous transmission of electrical energy and RF signals is based on the property of capacitors to change the resistance depending on the frequency of the current passing through them. Thus, the capacitor closes low-frequency currents, but does not interfere with the passage of high-frequency currents, i.e. their purpose is to prevent the passage of high-frequency currents into the ground, bypassing the RF post equipment.

Currently, a large number of communication capacitors are used in operation, which are one of the critical elements of the power system, the reliability of the networks depends on the reliability of their operation.

1. Reliability of the capacitor is its property to perform the specified functions in the specified operating conditions for the required period of time, while maintaining the performance in the specified range. Power capacitors are non-repairable products. The termination by the capacitor of the performance of its functions due to the occurrence of defects in it (breakdown, etc.) or a change in its parameters in excess of the permissible values at which a malfunction of the device in which it is installed is called its failure [G. Kuchinsky, Nazarov N.I. Power electric capacitors. M .: Energoatomizdat, 1992. - 320 p.].

Over the last years of operation, cases of destruction of capacitors caused by internal defects have become more frequent, which leads to serious consequences, such as: disconnection of consumers; equipment damage; and pose a threat to personnel when performing work in the substation.

The essence of this method is to determine the value of the capacitance of the coupling capacitor before putting it into operation, measuring the value of the capacitive current flowing through the coupling capacitor under the operating voltage, and the operating voltage of the network in real time, calculating the capacitance of the coupling capacitor from the measured current and voltage values, comparing the obtained value of the capacitance with the value of the capacitance of the coupling capacitor determined before commissioning, the diagnosis and monitoring of the technical condition of the object th capacitance value is calculated and compared continuously in real time, so that in the process of measuring the high-frequency communication channel is in use.

The process is fully automated, if there are no communication channels at the substation, the diagnostics of the communication capacitor can be performed "manually" with the frequency set at the enterprise.

In the automated process of diagnostics and monitoring of communication capacitors, information about their technical condition is transmitted to the upper level (network operator) in real time. There is also the possibility of storing, transmitting information about the parameters of the technical characteristics of the state of the coupling capacitor.

This method allows the network operator to obtain reliable information about the occurrence of defects in the capacitor at the initial stage of development in real time, and about its current state. This will allow avoiding emergencies in the power system, including at facilities remote over a considerable distance.

For coupling capacitors, the controlled parameters characterizing their technical condition, in accordance with regulatory and technical documents, are the capacitance of the capacitor and the dielectric loss tangent (hereinafter tgδ).

The current RD 34.45-51.300-97 “Volumes and norms of testing electrical equipment” regulates:

- "The capacitance is measured of each freestanding capacitor with its conclusion from work or under operating voltage (by measuring the capacitive current or voltage distribution on the series-connected capacitors)."

- “When monitoring capacitors under operating voltage, their condition is assessed by comparing the measured values of the capacitive current or capacitor voltage with the original data or values obtained for capacitors of other phases (connections).”

At the moment, the main method of monitoring the state is to measure the capacitance and tanδ (for the measurement of which it is necessary to take the equipment out of operation), or measure the capacitive current under operating voltage.

Measuring the capacitive current and comparing its values with the source data may not be sufficiently informative to assess the technical condition of the capacitor. Since the value of the current flowing through the capacitor depends on the voltage level applied to the capacitor, which can vary depending on the operating mode of the network.

Comparison of the measured current values with the values obtained for capacitors of other phases (connections) may also not be sufficiently informative to assess its condition, since:

1) Probably permissible differences between the measured currents of the compared capacitors of other phases (connections) are not indicated;

2) Capacitors have different values of the factory capacity, which affects the value of the currents flowing in them;

3) If there is a defect in several capacitors, there is no possibility of an objective assessment of the state;

4) There is no possibility of comparison when installing one capacitor in a substation.

The proposed method allows you to:

1. Constantly monitor the technical condition of capacitors in real time and identify defects at the initial stage of their development;

2. Eliminate the dependence of the controlled parameters (change in capacitance) on the applied voltage to the capacitor;

3. Timely take measures to exclude emergency situations that may occur when the capacitor is damaged;

4. Eliminate the potential danger to the operating personnel due to destruction of the capacitor;

5. Eliminate the need to withdraw equipment for diagnostics.

Let us consider in more detail the method of diagnosing and monitoring coupling capacitors under operating voltage.

To measure the value of the current flowing through a capacitor under operating voltage, it is proposed to use, as one of the elements of the diagnostic and monitoring system, a voltage extraction cabinet of the SHON type (mass production) (Figure - 2), which is intended for use in voltage selection circuits and synchronization from the coupling capacitor.

The current value is measured at the unused terminals of the secondary winding, one of two standard installed current transformers of the TON type. The primary current flowing through the capacitor is determined by the applied voltage, number and capacity of the elements. The magnitude of the current in the primary winding of the OET is equal to the product of the values of the measured current in the secondary winding and the working transformation coefficient, which is determined before putting the SHON into operation (in accordance with the requirement of the technical documentation for SHON).

Through a control cable connected to the terminals of the secondary winding of the TON, a multifunctional measuring transducer of parameters of the electric network is mounted, mounted in an electrical cabinet.

In the same cabinet it is proposed to install a device for collecting and transmitting information - a communication controller connected to the digital output of a multifunctional measuring transducer (Figure - 3).

It should be noted that the devices used (multifunctional measuring transducer and communication controller) are factory-made, without any structural changes being made by us.

An electrical cabinet is preferably mounted in a closed switchgear (switchgear, switchgear) to maintain the required temperature conditions.

The voltage from the secondary winding of the voltage measuring transformer is supplied through the control cables to the corresponding terminals of the multifunction measuring transducer.

The measured values of current and voltage are displayed on the built-in / remote display of the multifunctional measuring transducer, taking into account the entered transformation coefficients. The indicated information from the multifunctional measuring transducer is transmitted through a digital port via standard communication protocols via a communication controller via organized communication channels to the upper level (network operator's server). Installed specialized software on the server receives, processes and issues information in the client part of the software technical complex.

Data processing includes:

- Calculation of the capacitance of the capacitor according to the measured values of current and voltage in real time, according to the formula:

where U _l - interphase (linear) voltage of the network, kV;

ω is the angular frequency;

C _cs is the capacitance of the coupling capacitor, pF.

- Comparison of the calculated value of the capacitance in real time with the value of the capacitance of the coupling capacitor, determined before commissioning. If the capacitance value deviates by more than 2% (it is set by the enterprise depending on the type of capacitor used), the network operator displays a signal on the desktop on the capacitor malfunction at a specific object with an indication of the connection and phase.

In the absence of communication channels at the facility (substation), it is possible to diagnose the capacitor using the measured current and voltage data displayed on the display of the multifunction measuring transducer for further “manual” recalculation of the capacitance parameters (Figure - 4).

In the absence of a voltage transformer of the voltage class applied to the coupling capacitor, it is possible to use a voltage transformer of the lowest voltage class, with the subsequent calculation of the voltage value taking into account the transformation coefficient of the power transformer.

Consider one of the specific examples of the application of the considered method in practical application, in the laboratory. The object of measurements is a coupling capacitor of voltage class 110 kV.

The developer used equipment, instruments, devices, software:

- Communication capacitor type SMP-110 / 1,732-6,4 U1, manufacturer of Ust-Kamenogorsk Condenser Plant LLP, manufactured in 1980 (Figure - 1);

- A cabinet for selecting voltage type SHON-301C (manufacturer "ROSENERGOSERVICE", Russia, Rostov-on-Don, passport, TU 3433-005-46569277-2002, Figure - 2);

- Current transformer type TON-301C (included in the package of delivery SHON-301C);

- Multifunctional measuring transducer of electric network parameters of type SATEC РМ 130Р PLUS, Israel;

- Device for collecting and transmitting information - communication controller type Sincom IP / DIN, LLC "NTK Interface", Ekaterinburg;

- A mobile laboratory for high-voltage testing of the HVT-3AVG type based on the KAMAZ-43118 automobile manufactured by Yaroslavl Electromechanical Plant LLC, manufactured in 2015 (Certificate of registration of the electric laboratory No. 58 ETL 060, issued by: Federal Service for Ecological, Technological and Nuclear Supervision North- Ural Administration, validity period: November 05, 2018);

- Test transformer type TIM-100/20 kVA, manufactured by LLC "Yaroslavl Electromechanical Plant";

- Personal computer (hereinafter referred to as the server);

- Software of the software and hardware complex “OIC Dispatcher”, consisting of two parts: server and client, NTK Interface LLC, Ekaterinburg.

Stage 1. Preliminary work.

Before starting the application of the diagnostic and monitoring methods, the capacitor capacitance C _x was measured on the coupling capacitor under consideration (Table 1, p. 1), regulated by the standards [Alekseev B.A., Kogan F.L., Mamikonyanets L.G. "Scope and standards of testing of electrical equipment." - M .: ENAS, 2008. - 256 p.]. The measurements were carried out by an AC-bridge of type SA-7100 according to the normal measurement scheme from an external source at a voltage of 10 kV in accordance with current regulatory documents.

2. stage. The assembly of the measuring circuit for the application of the considered method, a description of the software.

2.1. An electrical cabinet (hereinafter - SHE) was assembled, the package of which included:

- A multifunctional measuring converter of electric network parameters of the type SATEC РМ 130Р PLUS (hereinafter referred to as the converter);

- A device for collecting and transmitting information - a communication controller such as Sinkom IP / DIN (hereinafter - the controller);

- Set of connecting wires;

- Terminal block.

2.2. A voltage selection cabinet of the SHON-301S type with two built-in current transformers of the TON-301S type is installed.

2.3. A high-voltage test laboratory was installed with the used transformer type TIM-100/20 kVA (hereinafter - IT).

2.4. A high-voltage wire is connected from the IT to the upper flange of the coupling capacitor mounted on an insulated stand. From the bottom of the capacitor shielded wire made connection to the SHON-301C through the insulator.

2.5. The control cable connected the secondary winding of the second (backup) current transformer TON-301C (terminals 7:10) to the converter.

2.6. The control cable made the connection to the secondary winding of IT and to the corresponding terminals of the converter.

2.7. Information from the converter is transmitted through a digital port using standard data transfer protocols via a communication controller via organized communication channels to a personal computer.

2.8. Description of the software.

a) A controller is used to organize the reception of data transmission. Transmitter polling is organized via RS-485 interface in Modbus protocol. The configuration of the communication controller is shown in Figure - 5. Basic settings:

- Exchange rate - 9600 bps;

- Transmission mode - 8 bits;

- Parity - Even;

- The exchange between the CP to the upper level (server) is organized in the UDP protocol.

b) For the polling, processing and storage of data at the upper level (server), specialized software PTK OIC Dispatcher is installed, consisting of two parts: server and client.

- Setting up the server side.

When setting up a telemechanical server, an object tree (structure) is formed, with a description of telemetry signals. The Figure - 6 shows the structure of the survey from KP to teleparameters. The configuration parameters of the Figure-7 communications will be configured. Next, the descriptive part of the Figure-8 structure will be formed.

In accordance with the addressing of the IIP registers, a description of the television measurements is made. Also, for each telemeasurement, a scale factor is indicated depending on the transformation coefficient. For processing and analysis of data virtual teleparameters with TIT (7-10) have been added, indicating the necessary calculations in the "Expression" line. Figures - 9. The possibility of requesting slices of television measurements for a certain period and averaging period is also configured.

- Setting up the client side.

To display the received data, the client part of the OIC “Dispatcher” is installed. In the client of the OIC “Dispatcher”, the visualization of the teleparameters is configured in the required volume, as well as with a fault signaling. Figure - 10.

3. stage. Taking measurements by the method.

3.1. An alternating voltage of industrial frequency 50 Hz equal to 60/65 kV (phase voltage, operating voltage of the network 110 kV) is supplied from the IT.

3.2. The conductivity current measured through the coupling capacitor in the secondary winding of TON-301C and the voltage in the secondary winding of IT are measured (Table - 1, p. 2, 3).

3.3. On the display of the converter we observe the measured values of current and voltage (taking into account the entered transformation coefficients).

3.4. Further, the received data from the converter is transmitted through a digital port using standard protocols through a controller to a server, where the software processes and issues information:

- Calculation of the capacitance of the capacitor according to the measured values of current and voltage (Formula - 1);

- Comparison of the calculated capacitance value, the capacitance values measured according to the normal measurement scheme.

4. stage. Dismantling the coupling capacitor, in order to change the capacitance, by cutting out several elementary capacitors (hereinafter referred to as sections), to create a model with a developing internal defect.

The coupling capacitor consists of four packets, with a series connection of sections alternately stacked on top of each other. The package includes plane-pressed sections impregnated with mineral condenser oil [Gulevich A.I., Kireev A.P. "Production of power capacitors." -M .: ENAS, 2008. - 256 p.].

The developers opened the coupling capacitor by removing the porcelain tire and shorted two sections (in order to simulate a developing defect). After that, the capacitor was again assembled, filled with mineral condenser oil, the characteristics of which comply with regulatory requirements [GOST 5775-85. "Condenser oil." - M.: USSR State Committee for Standards, 1985. - 4 p.].

5. stage. Carrying out measurements after opening and assembling the capacitor.

5.1. An alternating voltage of industrial frequency 50 Hz equal to 60/65 kV (phase voltage, operating voltage of the network 110 kV) is supplied from the IT.

5.2. The measurement of the conductivity current passing through the coupling capacitor in the secondary winding of TON-301C and the voltage in the secondary winding of IT (Table - 1, p. 3.4).

5.3. On the display of the converter we observe the measured values of current and voltage (taking into account the entered transformation coefficients).

5.4. Further, the received data from the converter is transmitted through a digital port using standard protocols through a controller to a server, where the software processes and issues information:

- Calculation of the capacitance of the capacitor according to the measured values of current and voltage (Formula - 1);

- Comparison of the calculated capacitance value, the capacitance values measured according to the normal measurement scheme.

6. From the work done, when using the method for diagnosing and monitoring the technical condition of the coupling capacitor under operating voltage, it is clearly seen that the current flowing through the capacitor and the voltage applied to it change linearly, depending on the change in the operating mode of the network, however, the calculated value of the capacitance, the main The coupling capacitor criterion is practically unchanged.

The developed method for diagnosing and monitoring the technical condition of communication capacitors under operating voltage allows:

1) Perform continuous monitoring and monitoring of the technical condition of the communication capacitor at the network operator in real time without the involvement of operational or repair personnel;

2) Promptly detect any deviations (defects) in the capacitor, respectively, and make the necessary decisions, which affects the reliability of the power system;

3) Eliminates the danger of staff due to destruction of the capacitor;

4) Eliminates the dependence of the controlled parameter (capacitance changes) on the applied voltage to the capacitor;

5) Eliminates the need to compare the measured values of the flowing current through the capacitor with the values obtained for capacitors of other phases (connections);

6) Eliminates the need to withdraw equipment for diagnostics.

Thus, the claimed method allows the operator of the power system (network) to obtain reliable information in real time about the technical condition of the communication capacitor, which is one of the critical elements of the power system, the reliability of which depends on the reliability of the networks at all controlled facilities where they are installed. And also to avoid, or in time to prevent emergencies (accidents) that may occur as a result of failure of the coupling capacitor.

Brief Description of the Drawings

The Figure - 1 shows the connection diagram of the voltage selection cabinet to the coupling capacitor.

The figure - 2 presents a schematic diagram of the cabinet voltage selection.

The Figure - 3 presents a diagram of the cabinet electrical diagnostics of the state of the coupling capacitor.

The Figure - 4 shows the connection diagram of a multifunctional measuring transducer.

The Figure - 5 shows the configuration of the communication controller.

The Figure - 6 shows the structure of the survey from KP to teleparameters.

The Figure - 7 presents the configuration structure of the communication parameters.

The Figure - 8 presents the structure of the narrative.

The Figure - 9 presents the structure of the description of television measurements.

The Figure - 10 shows the structure of the client part.

The implementation of the invention

Figure - 1.

The connection of the voltage selection cabinet (1) and the grounding knife (2) to the lower plate of the coupling capacitor (3) is made in series.

Figure - 2.

The voltage selection cabinet includes a 110 kV test transformer and 20 kVA power (5), a coupling capacitor (6), a bushing (7), a 30 pF capacitor (8), a 110 mH choke (9), a gas discharge (10), and an earthing knife ( 11), current transformers (12), connection filter (13). From the test transformer (5) to the coupling capacitor (6), an alternating phase voltage of industrial frequency 50 Hz is supplied equal to 60/65 kV, after which the conductivity current (I) passing through the coupling capacitor (6) in the secondary winding is measured (I ₂ ) current transformer (8) and voltage (U) in the secondary winding of the test transformer (5).

The figure is 3.

The cabinet electrotechnical includes a communication controller

Syncom IP (DIN) (14), power supply unit ~ 220V / = 24V DRAN30-24 (15), multifunctional measuring transducer SATEC PM130Plus (16), measuring terminals of current circuits (17), measuring terminals of voltage circuits (18), port RS-485 interface (19), feed-through power terminals (20). To organize the reception and transmission of data, a communication controller (14) is used, the power of which is supplied from the power supply unit (15) ~ 220V / = 24V (U / U ₁ ). The current and voltage circuits of the multifunction measuring transducer are connected through the measuring terminals (17, 18). The power supply ~ 220 V (U) of the electrical cabinet is connected via bushings (20).

The figure is 4.

The survey of the multifunctional measuring transducer (16) is organized via the RS-485 interface (19) through the software in the Modbus protocol.

Figures 5-9.

Shown sequentially settings of the software and hardware complex. The figure is 10.

A mimic diagram of the diagnostics of the state of a communication capacitor displayed on a network operator’s computer is shown.

Claims (1)

A method for diagnosing and monitoring the technical condition of communication capacitors under operating voltage, including determining the value of the capacitance of the communication capacitor before putting it into operation, measuring the capacitive current flowing through the coupling capacitor under the operating voltage, and the operating voltage of the network in real time, calculating the value of the capacitance of the coupling according to the measured values of current and voltage, comparing the obtained value of the capacitance with the value of the capacitance of the coupling capacitor, determined before commissioning, diagnostics and monitoring of the technical condition of the object, while the value of the capacitance is calculated and constantly compared in real time so that in the process of measuring the high-frequency communication channel is in operation.

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