Bus voltage loop line selection system

Abstract

The utility model relates to the technical field of bus voltage loop line selection of thermal power generation equipment, in particular to a bus voltage loop line selection system, which has the functions of independently sampling, transmitting and using bus voltage. The system is characterized in that in the bus voltage loop, a voltage line selection intermediate relay is additionally arranged between a PT secondary winding and a protection device, and the PT secondary winding provides secondary voltage required by the protection device; the protection device provides electric quantity protection for bus equipment; and the voltage line selection intermediate relay is specially used for providing voltage output for the voltage quantity required by the protection device. The protection device is simple in structure, remarkable in effect and low in investment cost, greatly reduces the influence of fault of a PT secondary circuit on maloperation and refusal of operation of the protection device, improves the action reliability of the protection device, and solves the problem of reliability of a bus voltage circuit; the protection device is prevented from malfunctioning and refusing to operate when primary equipment breaks down due to loss of voltage sampling, normal and stable operation of the bus protection device is ensured, and the health level of large-scale generator set equipment is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of bus voltage loop line selection for thermal power generation equipment, in particular to a system for bus voltage loop line selection. Background Art

[0002] With the rapid development of the power industry, relay protection devices are needed to ensure the safety and stability of the operation of the power system. At present, the microcomputer relay protection system for the bus system of thermal power generating units is increasingly widely used. During the applicant's use, it is found that once a fault occurs in the PT secondary circuit, the protection device will not be able to operate, resulting in misoperation or refusal to operate of the protection device. The fault problem of the bus protection device will affect the normal operation of the thermal power unit, not only affecting the safety of the equipment, but also affecting the stability of the power system. Moreover, each time a fault is eliminated, a relatively high cost is required, which affects the service life of the equipment and the accuracy of the data, and has relatively large potential safety hazards. Summary of the Invention

[0003] The purpose of the utility model is to solve the problem of the reliability of the voltage provided by the existing bus protection device. For this reason, on the basis of the existing bus protection system, a system for bus voltage loop line selection is provided.

[0004] The specific scheme of the utility model is: it has the functions of independently sampling, transmitting and using the bus voltage quantity. Its characteristics are: in the bus voltage loop, a voltage line selection intermediate relay is installed between the PT secondary winding and the protection device, and the PT secondary winding provides the secondary voltage quantity required by the protection device; the protection device provides electrical quantity protection for bus equipment; the voltage line selection intermediate relay specifically provides voltage output for the voltage quantity required by the protection device.

[0005] In the utility model, the accuracy of the PT secondary winding is 6P level, the secondary rated voltage is 57.7V, and the transformation ratio is Ratio Ratio 0.1 / 3KV

[0006] In the utility model, the protection device adopts a microcomputer protection device.

[0007] In the utility model, the voltage line selection intermediate relay adopts a DC 110V or 220V voltage input, 4 pairs of normally open contacts, and 2 pairs of normally closed contacts.

[0008] The utility model has a simple structure, remarkable effects and low input cost, greatly reducing the influence of faults in the PT secondary circuit on the misoperation and refusal of the protection device, improving the action reliability of the protection device, solving the reliability problem of the bus voltage circuit; preventing the misoperation and refusal of the protection device caused by the loss of voltage sampling, ensuring the normal and stable operation of the bus protection device, and ensuring the health level of large generator set equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of the primary of the bus voltage transformer of the utility model;

[0010] Figure 2 is a schematic circuit diagram of the voltage selection intermediate relay circuit of the utility model;

[0011] Figure 3 is a schematic circuit diagram of the voltage circuit of the protection device of the utility model;

[0012] In the figure: 1 - bus, 2 - secondary winding of phase A of PT, 3 - secondary winding of phase B of PT, 4 - secondary winding of phase C of PT, 5 - PT switch, 6 - PT start-up auxiliary contact 1, 7 - PT start-up auxiliary contact 2, 8 - voltage selection intermediate relay 1, 9 - voltage selection intermediate relay 2, 10 - auxiliary contact 1 of voltage selection intermediate relay 1, 11 - auxiliary contact 2 of voltage selection intermediate relay 1, 12 - auxiliary contact 3 of voltage selection intermediate relay 1, 13 - auxiliary contact 1 of voltage selection intermediate relay 2, 14 - auxiliary contact 2 of voltage selection intermediate relay 2, 15 - auxiliary contact 3 of voltage selection intermediate relay 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] See Figures 1-3 , the utility model is a system for selecting lines in the bus voltage circuit, characterized in that: in the bus voltage circuit: a voltage selection intermediate relay is installed between the PT secondary winding and the protection device, and the PT secondary winding provides the secondary voltage required by the protection device; the protection device provides electrical quantity protection for bus equipment; the voltage selection intermediate relay specifically provides voltage output for the voltage required by the protection device.

[0014] In the switch current circuit: current transformers 6, 7, 8 are installed between the secondary windings 2, 3, 4 of the CT and the 6KV switch comprehensive protection device 9. The secondary windings 2, 3, 4 of the CT provide the input of the secondary current required by the 6KV switch comprehensive protection device 9 and the current transformers 6, 7, 8; the 6KV switch comprehensive protection device 9 provides the electrical quantity protection function for the 6KV switch 1; the current transformers 10, 11, 12 specifically provide output for the DCS system 13 to display current indication.

[0015] In the present utility model, the PT secondary winding has an accuracy of class 6P, a secondary rated voltage of 57.7V, and a transformation ratio of Ratio Ratio 0.1 / 3KV

[0016] In the present utility model, the protection device adopts a microcomputer-based protection device.

[0017] In the present utility model, the voltage selection intermediate relay adopts a DC 110V or 220V voltage input, 4 pairs of normally open contacts, and 2 pairs of normally closed contacts.

[0018] This embodiment greatly ensures the safe and orderly operation of the #210 unit, reduces the occurrence of fault problems, reduces the costs consumed in the process of fault analysis and elimination in the past, and further realizes the safe production and energy conservation and consumption reduction of our factory.

Claims

1. A bus voltage circuit selection system, which has the function of independently sampling, transmitting and using bus voltage; its characteristics are: In the bus voltage circuit: a voltage line selection intermediate relay is installed between the PT secondary winding and the protection device, the PT secondary winding provides the secondary voltage required by the protection device; the protection device provides electrical quantity protection for the bus equipment; the voltage line selection intermediate relay specifically provides voltage output for the voltage required by the protection device.

2. A bus voltage loop line selection system according to claim 1, characterized in that: The PT secondary winding accuracy is 6P, the secondary rated voltage is 57.7V, and the transformation ratio is Compare Ratio 0.1 / 3KV.

3. A bus voltage loop line selection system according to claim 1, characterized in that: The protection device adopts a microcomputer type protection device.

4. A bus voltage loop line selection system according to claim 1, characterized in that: The voltage line selection intermediate relay adopts a DC 110V or 220V voltage input, 4 pairs of normally open contacts, and 2 pairs of normally closed contacts.

Images