RU2265861C1 - Device for checking condition of equipment with condenser-type paper-oil isolation - Google Patents

Abstract

FIELD: equipment for diagnosing high-voltage equipment.

SUBSTANCE: device is intended for continuous checking equipment with paper-oil isolation (high-voltage wires, current transformers etc.) having rated voltage of 110 kV and higher. Device has preliminary and final signal processing units connected together and signaling device. Preliminary signal processing unit has members for connecting object to measuring terminals of phases to provide connection with measurement unit which has primary converters connected with unit of preliminary signal processing and digitization unit. Measurement unit has communication interface connected with digitization unit. Signal final processing unit has PC and data collection unit on the base of industrial computer. One output of the latter is connected with PC and its input is connected with signal preliminary processing unit through communication line. As primary converters the resistors are used. Digitization unit is made multi-channel one and has analog-to-digital converters for corresponding phases. Outputs of the phases are connected with microcontroller.

EFFECT: detection of leakage in insulators at early stage.

3 cl, 6 dwg

Description

The invention relates to a technique for diagnosing high voltage electrical equipment and is intended for continuous monitoring of equipment with paper-oil insulation of a capacitor type (high voltage bushings, current transformers) with a rated voltage of 110 kV and higher.

A device for automatically monitoring the state of insulation of high-voltage equipment (AS No. 296062, IPC G 01 R 31/02, G 01 R 31/08,) comprising an input adder block of two adders that sums the currents of two monitored objects, measuring and signal units which are included in the difference of the output currents of the adders. To control two non-identical three-phase objects, the adders are equipped with adjustable regulators during commissioning.

There is also known a device for automatically monitoring the state of insulation of high-voltage equipment (AC N 384080, IPC G 01 R 31/12), which in addition to the device according to AC N 296062 contains three resistances, each of which is connected between the adder and the corresponding phase of the monitored mains through a voltage transformer.

Closest to the proposed solution is a control system for insulation of high-voltage bushings (RF patent No. 2145420, IPC G 01 R 31/08, G 01 R 31/12), containing devices for connecting to three-phase high-voltage bushings, the outputs of which are connected to the inputs of the corresponding instrument transformers current, a voltage transformer of a three-phase high-voltage bus system, the outputs of which are connected to the inputs of the corresponding instrument voltage transformers, an alarm device, two phase shifters connected to the outputs of two of the three instrument transformers torus currents, ADC and microprocessor.

The disadvantage of these devices is the impossibility of centralized monitoring with data archiving, the impossibility of determining false alarms, as well as the use of a current transformer in these devices, which complicates their operation due to the need for periodic verification.

The objective of the proposed solution is continuous centralized monitoring of condenser-type paper-oil equipment (high voltage bushings, current transformers) in order to detect leaks in insulators at an early (pre-emergency) stage without shutting down this equipment.

The problem is solved in that a device for monitoring the condition of equipment with paper-oil insulation of a capacitor type, containing connected signal pre-processing, signal final processing and signaling units, while the signal pre-processing unit includes elements for connecting the object to the phase measurement inputs with the possibility of connecting to a measurement unit, a primary converter for each phase, each of which is connected to an analog signal preprocessing unit and a digitizing unit, according to the proposed solution, a communication interface is inserted into the measuring unit connected to the digitizing unit, and the signal final processing unit contains a personal computer and an information collection unit based on an industrial computer, one output of which is connected to a PC, the second to the signaling device, and the input connected to the signal preprocessing unit over the communication line, while the digitizing unit is multi-channel and contains analog-to-digital converters for the corresponding phases, the outputs of which are connected to to the controller.

The device further comprises several signal preprocessing units connected in parallel to the communication line.

The device further comprises a switching and emergency protection unit, connection elements are connected to the measurement unit through a switching and emergency protection unit, which contains input signal jumper connected to each phase with a parallel connected and grounded gas spark gap, resistor and contactor, and each primary converter is made in in the form of two parallel-connected resistors, one of which is in the switching and emergency protection unit, and the second - in the pre-processing unit a alogovogo signal.

The invention is illustrated by drawings, in which Fig. 1 is a block diagram of the device as a whole, in Fig. 2, in Fig. 3 is a vector diagram, in Fig. 4 is an equivalent circuit of a high voltage input, Fig. 5 is a circuit diagram of a single BKAZ channel, FIG.6 is a block diagram of a measurement block, where:

1 - signal preprocessing unit (BPOS)

2 - block final signal processing (BOOS)

3 - signaling device

4 - elements of the connection of the object (EPO)

5 - measurement unit (BI)

6 - information collection unit (BSI)

7 - personal computer (PC) operator

8 - switching unit and emergency protection (BKAZ)

9 - jumper

10 - gas spark gap

11 - resistor

12 - contactor

13 - resistor

14 - block pre-processing of the analog signal (BPOAS)

15 - block digitization (BO)

16 - communication interface (IP)

C d1, Cd 2 - equivalent input capacitance

R _ut - leakage resistance

Each set of BPOS 1 includes elements for connecting the object EPO 4, the switching unit and emergency protection BKAZ 8 and the measuring unit BI 5.

Elements of connection of the object EPO 4 performs the function of connecting the measurement leads of the high voltage inputs to the input terminals of the BKAZ 8.

The switching unit and emergency protection BKAZ 8 is designed to connect the measuring path of the BPOS kit 1 to the connection elements of the EPO 4, the implementation of the first stage of emergency protection, isolation of input voltages on the elements of the primary converters - resistors 11 and the supply of input voltages to the measuring unit BI 5 through a connecting cable. In addition, BKAZ 8 provides grounding of input phase lines to ensure safety when working with BI 5

The BI 5 measurement unit performs the functions of isolating input voltages on the second elements of the primary converters - resistors 13 (including the 2nd and 3rd steps of measuring path protection), processing analog signals to the required level, digitizing the signals, issuing information in the form of code messages in a line communication with BSI 6. BSI 6 performs a two-way exchange of information with BI 5, by controlling the operating modes of BI 5 and reading the digitized signal values.

The device operates as follows.

The voltages from the measuring plates of the inputs of the controlled equipment are fed through the connection elements of the EPO 4 to the input of the BKAZ 8. Then they pass into the measuring path through the jumpers 9 corresponding to each phase. Gas dischargers 10 form the first stage of protection of the measuring path. The switch 12 in the operating position is open, but closes the phase lines to the ground to ensure safety during maintenance work with BI 5.

The resistor, which is the primary converter, is structurally divided into 2 parallel-connected resistors 11 and 13, one of which is located in BI 5, and the other (11) is placed in BKAZ 8, to increase reliability and safety. Separation of the BKAZ 8 into a separate unit allows disconnecting jumper 9 to connect measuring instruments to the measuring output of the high voltage input during the prevention of high voltage equipment without raising personnel to high located high voltage inputs, or to perform BPOS prophylaxis by applying test signals to the inputs of the phase measuring channels after jumper 9.

Voltages from BKAZ 8 through a 4-wire cable (phases A, B, C and 0) are supplied to BI 5, to the input of the pre-processing unit of the analog signal, consisting, along the voltage path of each phase, from the second element of the primary converter - resistor 13, switched voltage divider and 2nd and 3rd stages of protection, preventing the input of electronic devices from interference voltages and pickups of a dangerous level.

Next, the phase voltages from the pre-processing unit of the analog signal 14 are supplied to the BO 15 analog-to-digital converters controlled from the BO 15 microcontroller. At fixed times, measurements are made, the results of which are converted to digital form. Further, the microcontroller BO 15 accumulates the received data in the random access memory BO 15, and upon request transfers them to BSI 6.

Processing the obtained data and calculating the parameters of the source signals is carried out programmatically in BSI 6, where the program converts the received data into a convenient form for reading and storage.

Between the controller and the communication line is a bi-directional communication interface 16, which provides galvanic isolation and coordination of signal levels between the controller and the communication line.

BSI 6 operating mode is controlled from operator PC 7 through the program installed on it.

BSI 6 processes data from all sets of BPOS 1, stores it in a database and communicates with the personal computer of operator 7. In addition, BSI 6 generates a signal to trigger an external light or sound alarm 3 device according to a specified criterion.

All signal processing is carried out after they are digitized by software using the industrial computer software included in BSI 6.

With good quality high-voltage input (leakage current through R _{ut is} negligible) and the equality of the modules of the phase vectors, the sum of the three phases is 0 (Fig.2).

When a noticeable value of R _y appears, the phase angle changes and, accordingly, the sum of the vectors U _sum becomes nonzero (Fig. 3).

The set of data representing the instantaneous voltage values of the analyzed signal, measured at fixed intervals of time, is processed by the mathematical apparatus of the industrial computer program BSI 6, which processes the necessary parameters of the input signal, and thus determines the parameters of the complex conductivity of the capacitive divider (figure 4) , on the basis of which, according to the criteria for leakage standards stored in the computer’s memory, the suitability of this input for further operation is determined tatsii.

In order to detect the difference in the “drawdown” of the voltage of one phase due to the uneven load from the change in the module of the phase vector due to leakage in this input, the computer compares the readings of different sets of BPOS connected to the same phase, thus developing a criterion for normalizing the voltage of this phase.

To increase reliability and maintain metrological stability, measurement units operating in the open air are equipped with a heating device that automatically maintains a positive temperature in the BI case in the cold season.

BSI 6 of this device allows, in addition to the main alarm device, to connect up to 7 additional signaling devices.

This device allows, in addition, using the local area network (LAN) of the enterprise, to connect to BSI 6, in addition to the operator’s PC, the personal computers of the responsible persons of the enterprise.

User software options leading to changes in device parameters are password protected.

Claims (3)

1. A device for monitoring the state of equipment with paper-oil insulation of a capacitor type, containing connected signal preprocessing, signal final processing and signaling units, while the signal preprocessing unit includes elements for connecting the object to the phase measurement inputs with the possibility of connecting to the measurement unit, primary a converter for each phase, each of which is connected to an analog signal preprocessing unit and a digitizing unit, characterized in that a communication interface connected to the digitization block is entered into the measurement unit, and the signal final processing unit contains a personal computer (PC) and an information collection unit based on an industrial computer, one output of which is connected to a PC, the second to a signaling device, and the input is connected to a signal preprocessing unit over the communication line, while the digitizing unit is multi-channel and contains analog-to-digital converters for the corresponding phases, the outputs of which are connected to the microcontroller. 2. The device according to claim 1, characterized in that it further comprises several signal preprocessing units connected in parallel to the communication line. 3. The device according to claim 1, characterized in that it further comprises a switching and emergency protection unit, connection elements are connected to the measurement unit through a switching and emergency protection unit, which contains input signal jumpers connected to each phase with parallel and grounded gas a spark gap, a resistor and a contactor, and each converter is made in the form of two resistors connected in parallel, one of which is in the switching and emergency protection unit, and the second is in the pre ritelnoy processing the analog signal.

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