CN102694377A - Microcomputer-type power transmission temporary protection device - Google Patents

Abstract

The microcomputer power transmission temporary protection device relates to a power transmission temporary protection device, which is to solve the problem of low temporary protection sensitivity, low setting precision, serious secondary burden, and easy current circuit failure problem. The analog acquisition signal of its No. 1 analog acquisition circuit is converted by the No. 1 analog/digital conversion circuit and then input to DSP; DSP and CPLD perform data interaction; the relay control signal output of DSP and the relay control signal output of CPLD are both Connect with the relay control signal input terminal of the export relay; one end of the export relay is connected with one end of the electromagnetic switch; the analog quantity acquisition signal of the No. 2 analog quantity acquisition circuit is converted by the No. 2 analog/digital conversion circuit and connected with the digital signal input terminal of the CPU Connection; data interaction between DSP and CPU; CPU controls electromagnetic switch action. The invention is suitable for temporary protection of power transmission.

Description

Microcomputer Power Transmission Temporary Protection Device

technical field

The invention relates to a temporary protection device for power transmission.

Background technique

The reliability of 500 kV backbone grid power supply is becoming more and more important, and with the rapid growth of the national economy, new 500 kV lines and transformers are becoming more and more frequent. When new equipment is put into operation, considering the uncertainty of new equipment and temporary changes in system operation mode, it is necessary to ensure the safe and reliable operation of new equipment and the safety of the original system from the aspect of relay protection, so it must be installed when power transmission temporary protection.

If the temporary protection method is improper during the commissioning process, it may cause unnecessary actions of the protection, and even expand the accident when the fault occurs. Therefore, the reliability and safety of the 500 kV backbone grid power supply during power transmission are all maintained by the temporary protection. The temporary protection currently used is the traditional relay type, which has large errors and low precision. When errors or malfunctions occur, it may threaten the reliability of the power supply of the 500 kV backbone grid.

At present, most of the temporary protection used in the new 500 kV line is the traditional relay type, which has the disadvantages of large size, aging relay coil, large setting error, small setting range, low precision, and insufficient tripping outlets. It cannot be better To fully meet the requirements of safe and stable operation of relay protection, there are many inconveniences and unsafe factors in field use. There are mainly the following disadvantages:

1. It is inconvenient to install and carry. The traditional electromagnetic relay type temporary protection has a large volume and weight, and it is inconvenient to carry and connect at the work site, which reduces work efficiency.

2. The sensitivity is not enough. When new lines and new equipment are put into operation, reliable protection is required as a guarantee, so sufficient sensitivity is required. Generally, the setting value is set according to the sensitivity ≥ 1.5, and the temporary setting value needs to ensure that any phase-to-phase fault and ground fault can trip quickly. The current traditional electromagnetic relay type temporary protection is not sensitive enough.

3. The setting precision of fixed value is not high. In order to ensure that the failure of the starting equipment can be quickly removed, the time setting value should be as short as possible. However, the current field electromagnetic relay type temporary protection setting value setting method is complicated, with large setting error, small setting range and low accuracy.

4. Temporary protection increases the secondary burden. Because the traditional electromagnetic relay type temporary protection is an electromagnetic current relay, the resistance of the current coil is large, and it needs to be connected in series with the current loop when used, which can easily cause the secondary burden to exceed the standard, resulting in an increase in TA error, and the secondary transmission current cannot correctly reflect the primary current. The situation is not conducive to the normal operation of the equipment.

5. When the traditional electromagnetic temporary protection is connected in series with the current loop, the terminal connection method is used. Improper operation or poor contact of the temporary protection wiring may lead to TA open circuit, increasing the possibility of failure of the current loop.

6. The trip contacts of the temporary protection are generally connected to the permanent trip circuit of the operation box, but there are contacts for charging protection, failure protection, bus differential protection and other protections on the permanent circuit circuit. In the case of limited terminal blocks, one terminal is required , Therefore, when the temporary protection trip contact is connected or removed, it may lead to poor contact of the trip circuit wiring and affect the protection action.

Contents of the invention

The present invention aims to solve the problems of low temporary protection sensitivity, low setting precision, serious secondary burden, and easy failure of the current loop in the existing temporary protection device for power transmission, thereby providing a temporary protection device for power transmission with a microcomputer device.

Microcomputer power transmission temporary protection device, which includes No. 1 analog quantity acquisition circuit, No. 1 analog/digital conversion circuit, DSP, CPLD, optical isolation circuit, export relay, electromagnetic switch QDJ, No. 2 analog quantity acquisition circuit, No. 2 Analog/digital conversion circuit and CPU;

The analog quantity acquisition signal output end of No. 1 analog quantity acquisition circuit is connected with the analog quantity acquisition signal input end of No. 1 analog/digital conversion circuit; the digital signal output end of described No. 1 analog/digital conversion circuit is connected with the digital signal input of DSP The signal input or output terminal of DSP is connected with the signal output or input terminal of CPLD; the relay control signal output terminal of DSP and the relay control signal output terminal of CPLD are connected with one end of the control coil of the export relay; the export relay The other end of the control coil is connected to one end of the electromagnetic switch QDJ; the other end of the electromagnetic switch QDJ is connected to the +E power supply;

The input end of the optical isolation circuit is the input end of the external input signal; the output end of the optical isolation circuit is connected with the optical isolation signal input end of the CPLD;

The analog quantity acquisition signal output end of the No. 2 analog quantity acquisition circuit is connected with the analog quantity acquisition signal input end of the No. 2 analog/digital conversion circuit; the digital signal output terminal of the No. 2 analog/digital conversion circuit is connected with the digital signal input of the CPU Terminal connection; No. 2 signal input or output terminal of DSP is connected with signal output or input terminal of CPU; electromagnetic switch control signal output terminal of CPU is connected with control signal input terminal of electromagnetic switch QDJ.

Beneficial effects: the present invention combines the circuit breaker microcomputer protection with on-site temporary protection functions, and develops a microcomputer temporary protection device with complete functions, small errors, high precision and strong reliability, which can significantly improve the time when new equipment and lines are put into operation. The reliability of the temporary protection action will greatly improve the reliability of the power supply of the 500 kV backbone grid. The present invention has high sensitivity of temporary protection, high precision of setting value, no secondary burden, and is not easy to cause failure of current loop.

Description of drawings

Fig. 1 is a schematic structural diagram of the present invention; Fig. 2 is a schematic flow chart of the temporary protection of the present invention; Fig. 3 is a schematic diagram of the protection logic of the present invention.

Detailed ways

The specific embodiment one, in conjunction with Fig. 1 to Fig. 3 illustrate this specific embodiment, the computer power transmission temporary protection device, it comprises No. 1 analog quantity acquisition circuit 1, No. 1 analog/digital conversion circuit 2, DSP3, CPLD4, light Isolation circuit 5, export relay 6, electromagnetic switch QDJ, No. 2 analog quantity acquisition circuit 7, No. 2 analog/digital conversion circuit 8 and CPU9;

The analog quantity acquisition signal output end of the No. 1 analog quantity acquisition circuit 1 is connected with the analog quantity acquisition signal input end of the No. 1 analog/digital conversion circuit 2; the digital signal output terminal of the No. 1 analog/digital conversion circuit 2 is connected with the DSP3 The digital signal input terminal is connected; the No. 1 signal input or output terminal of DSP3 is connected with the signal output or input terminal of CPLD4; the relay control signal output terminal of DSP3 and the relay control signal output terminal of CPLD4 are both connected with one end of the control coil of the export relay 6 ; The other end of the control coil of the export relay 6 is connected to one end of the electromagnetic switch QDJ; the other end of the electromagnetic switch QDJ is connected to the +E power supply;

The input end of optical isolation circuit 5 is the input end of external input signal; the output end of optical isolation circuit 5 is connected with the optical isolation signal input end of CPLD4;

The analog acquisition signal output end of No. two analog acquisition circuit 7 is connected with the analog acquisition signal input end of No. two analog/digital conversion circuit 8; the digital signal output end of described No. two analog/digital conversion circuit 8 is connected with CPU9's The digital signal input terminal is connected; the No. 2 signal input or output terminal of DSP3 is connected with the signal output or input terminal of CPU9; the electromagnetic switch control signal output terminal of CPU9 is connected with the control signal input terminal of electromagnetic switch QDJ.

The present invention collects No. 1 analog quantity acquisition circuit 1 and No. 2 analog quantity acquisition circuit 7 to carry out analog quantity acquisition, after carrying out analog/digital conversion respectively, send to DSP3 and CPU9, DSP3 and CPU collect the maximum value Imax of the three-phase current Compared with the preset standard current Icd value, if the preset standard current Icd value is exceeded, the temporary protection action is started after setting the protection time fixed value.

For a 500kV substation with a three-half connection mode, the present invention can access the secondary current of two current transformers connected to the line, and can set multiple groups of trip outlet pressure plates.

The invention realizes the computerization of the temporary protection, and has accurate setting value, convenient and fast setting value setting, stable and reliable device performance, high sensitivity precision, flexible selection of output trip outlet, and strong anti-interference ability. Can achieve fixed value and action report printing. The microcomputer temporary protection realizes functional integration, the device is small in size and simple in structure, which is convenient for on-site transfer, installation and wiring. It can significantly improve the speed of temporary protection installation, fixed value setting speed and accuracy when new equipment and lines are put into operation, and improve work efficiency. At this time, in the event of a fault, the accurate action rate of the protection improves the reliability of the power supply of the 500 kV backbone grid.

Specific embodiment two, the difference between this specific embodiment and the microcomputer power transmission temporary protection device described in specific embodiment one is that it also includes a power supply liquid crystal display circuit 10, and the display signal input terminal of the power supply liquid crystal display circuit 10 Connect with the display signal output terminal of DSP3.

In this embodiment, the current current value can be displayed in real time through the liquid crystal display circuit 10 of the power supply.

Specific embodiment three, the difference between this specific embodiment and the microcomputer power transmission temporary protection device described in specific embodiment one is that it also includes a printing device 11, and the printing device 11 communicates with the CPU9 through a serial or parallel data bus. connect.

This embodiment provides a printing device to realize the output of the current value.

Embodiment 4. The difference between this embodiment and the computer power transmission temporary protection device described in Embodiment 1 is that it also includes a serial interface 12, and the serial interface 12 is connected to the serial port of the CPU9. .

This embodiment provides a serial interface 12 to realize the serial connection between the CPU and external devices.

Claims (4)

1. microcomputer type send electric temporary protection device, it is characterized in that: it comprises that an analog acquisition circuit (1), mould/number conversion circuit (2), DSP (3), CPLD (4), light are at a distance from circuit (5), exit relay (6), electromagnetic switch (QDJ), No. two analog acquisition circuit (7), No. two mould/number conversion circuit (8) and CPU (9);

The analog acquisition signal output part of an analog acquisition circuit (1) is connected with the analog acquisition signal input part of a mould/number conversion circuit (2); The digital signal output end of a said mould/number conversion circuit (2) is connected with the digital signal input end of DSP (3); The signal of DSP (3) inputs or outputs end and is connected with signal output or the input of CPLD (4); The relay control signal output of the relay control signal output of DSP (3) and CPLD (4) all is connected with an end of the control coil of exit relay (6); The other end of the control coil of this exit relay (6) is connected with an end of electromagnetic switch (QDJ); Other end connection+E the power supply of said electromagnetic switch (QDJ);

Light is that the input into signal is opened in the outside at a distance from the input of circuit (5); Light is connected at a distance from signal input part with the light of CPLD (4) at a distance from the output of circuit (5);

The analog acquisition signal output part of No. two analog acquisition circuit (7) is connected with the analog acquisition signal input part of No. two mould/number conversion circuit (8); The digital signal output end of said No. two moulds/number conversion circuit (8) is connected with the digital signal input end of CPU (9); No. two signals of DSP (3) input or output end and are connected with signal output or the input of CPU (9); The electromagnetic switch control signal output ends of CPU (9) is connected with the signal input end of electromagnetic switch (QDJ).

2. microcomputer type according to claim 1 send electric temporary protection device, it is characterized in that it also comprises power supply liquid crystal display circuit (10), and the shows signal input of said power supply liquid crystal display circuit (10) is connected with the shows signal output of DSP (3).

3. microcomputer type according to claim 1 send electric temporary protection device, it is characterized in that it also comprises PRN device (11), and said PRN device (11) is connected with CPU (9) through the serial or parallel data/address bus.

4. microcomputer type according to claim 1 send electric temporary protection device, it is characterized in that it also comprises serial line interface (12), and said serial line interface (12) is connected with the serial port of CPU (9).

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