CN104035003A - Single-segmented-bus parallel-PT logic judgment method for selecting line with small grounding current - Google Patents

Abstract

The present invention relates to the technical field of relay protection for electric power systems, in particular to a logic judgment method for single-bus section PT parallel small current grounding line selection. The logical relationship between the switch and the PT switch node performs real-time switching of the PT signals of the I segment and the II segment. This method is conducive to improving the accuracy and reliability of line selection.

Description

Logical Judgment Method for Parallel Small Current Grounding Line Selection of Segmented PTs on Single Busbar

technical field

The invention relates to the technical field of electric power system relay protection, in particular to a logic judgment method for single-bus section PT parallel small-current grounding line selection.

Background technique

Substations of 110kV and below in my country mostly adopt the main wiring form of single bus section. The connection switch in the middle of the two sections of bus is the section switch of the bus. Any line can only be connected to section I or section II bus. After the single busbar is divided into sections, different sections can be used to supply power to important users. When a section of the bus fails, the section circuit breaker can automatically cut off the fault to ensure uninterrupted power supply to the normal section of the bus. When the bus PT is overhauled, the PT is out of operation, and at this time the section switch is in the closed position, the PT voltage of another section of the bus can be automatically paralleled to the PT input terminal in the overhaul state of the measurement and protection device, so that To ensure the accuracy of the measurement and the normal operation of the protection device. However, there are a considerable number of substations that have not installed PT parallel devices, or some equipment has not been connected to the small bus bar of PT, so that the equipment cannot obtain the correct signal under the above circumstances.

Small current grounding line selection equipment is a common equipment in 110kV and below substations, which undertakes the functions of small current grounding fault detection, line selection, tripping or alarm. When the segment switch is closed and one of the PTs is overhauled, if the PT signal cannot be effectively switched, the function of the line selection equipment will inevitably be lost. Patent CN102495330A Realization method of adaptive bus-tie operation mode of small-current grounding line selection device describes a method for judging bus-tie operation mode of small-current grounding line selection device, but does not elaborate on PT signal switching and its logic judgment method.

Contents of the invention

The purpose of the present invention is to provide a logic judgment method for line selection of single-bus section PT parallel small current grounding, which is beneficial to improve the accuracy and reliability of line selection.

The technical scheme adopted in the present invention is: a single-bus section PT parallel small current grounding line selection logic judgment method, which collects the information of the section switch and PT switch node signals in real time, and analyzes the connection between the section switch and the PT switch node. Logical relationship, real-time switching of PT signals of segment I and segment II.

The single-bus section PT parallel small current grounding line selection logic judgment method of the present invention includes the following steps:

Step 1, read the node information of the segment switch, segment I PT switch and segment II PT switch;

Step 2, judge the state of the section switch, if it is open, directly enter the line selection module; if it is closed, go to step 3;

Step 3, if the PT switch of section I is open and the PT switch of section II is closed, assign the value of the PT signal of section II to the PT switch of section I and enter the line selection module; if the PT switch of section II is open and the PT switch of section I is closed, set the The value of the segment PT signal is assigned to the II segment PT switch and enters the line selection module; if the I segment PT switch and the II segment PT switch are opened or closed at the same time, an alarm will be issued.

The beneficial effects of the present invention are: by collecting the switch state node signals, the logical relationship is judged, so as to realize the soft switching of the PT signal. This method does not need to manually change the configuration, which ensures the accuracy and reliability of line selection.

Description of drawings

Fig. 1 is a schematic diagram of signal access under the main wiring of the single bus section system in the embodiment of the present invention.

Fig. 2 is a flow chart of the realization of the logic judgment method in the embodiment of the present invention.

Detailed ways

In order to explain the advantages of the present invention more clearly, the semi-invention will be further described in detail below with reference to the drawings and specific embodiments. Many specific examples are listed in the following description in order to fully understand the advantages of the present invention, but the present invention can also be implemented in other ways different from those described here, so the present invention is not limited to the specific examples disclosed below.

The single bus segment PT parallel small current grounding line selection logic judgment method provided by the present invention collects the information of the segment switch and the PT switch node signal in real time, and analyzes the logical relationship between the segment switch and the PT switch node for section I Real-time switching with the PT signal of section II.

As shown in Figure 1, it is a schematic diagram of signals connected to the line selection device under the main wiring of the single bus section system. Between the I section bus and the II section bus is a section switch L1. The switch K1 of PT1 of section I busbar, the switch K2 of PT2 of section II busbar.

The node information of segment switch L1, switch K1 of PT1 and switch K2 of PT2 is connected to the digital input module of the small current grounding line selection device.

The voltage signals of PT1 and PT2 are connected to the voltage signal acquisition module of the small current grounding line selection device.

The zero-sequence current of each outgoing line is connected to the zero-sequence CT signal acquisition module of the small current grounding line selection device.

After the signal is connected to the device, the acquisition signal processing module processes the input digital and analog quantities in real time.

The logic algorithm module soft-switches the voltage signals of PT1 and PT2 in real time according to the real-time information of the nodes of segment switch L1, switch K1 of PT1, and switch K2 of PT2. As shown in Figure 2, it is a flow chart of the implementation of the logical determination method in the embodiment of the present invention, and the logical determination method includes the following steps:

Step 1, read the node information of the segment switch, segment I PT switch and segment II PT switch;

Step 2, judge the state of the section switch, if it is open, it means that the busbars of section I and section II are running in sections, then do not switch the PT signals of section I and section II, and directly enter the line selection module; if it is closed, Indicates that the busbars of section I and section II run in parallel, then go to step 3;

Step 3, according to the node information of the I-section PT switch and the II-section PT switch, judge the working status of the I-section PT switch and the II-section PT switch, and assign the PT signal in the working state to the PT signal of the other section; if running in parallel Next, if the PT switches of section I and section II are closed or open at the same time, an alarm will be issued. Specifically, if the PT switch of section I is open and the PT switch of section II is closed, assign the value of the PT signal of section II to the PT switch of section I and enter the line selection module; if the PT switch of section II is open and the PT switch of section I is closed, the I The value of the segment PT signal is assigned to the II segment PT switch and enters the line selection module; if the I segment PT switch and the II segment PT switch are opened or closed at the same time, an alarm will be issued.

The above logical judgment method can be realized by using the switch node information, without complex calculation, and can conveniently realize the soft switching of PT signals in the program of the line selection device.

The above are the preferred embodiments of the present invention, and all changes made according to the technical solution of the present invention, when the functional effect produced does not exceed the scope of the technical solution of the present invention, all belong to the protection scope of the present invention.

Claims (2)

1. a sectionalized single busbar connection PT small current earthing wire-selecting logic decision arranged side by side method, it is characterized in that, the information of Real-time Collection block switch and PT switching node signal, by analyzing the logical relation between block switch and PT switching node, switches in real time to the PT signal of I section and II section.

2. sectionalized single busbar connection PT according to claim 1 small current earthing wire-selecting logic decision arranged side by side method, is characterized in that, comprises the following steps:

Step 1, reads the nodal information of block switch, I section PT switch and II section PT switch;

Step 2, judges the state of block switch, and open mode if, directly enters route selection module; Closure state if, goes to step 3;

Step 3, if I section PT switch opens, II section PT switch closure, is assigned to I section PT switch by the value of II section PT signal, enters route selection module; If II section PT switch opens, I section PT switch closure, is assigned to II section PT switch by the value of I section PT signal, enters route selection module; If I section PT switch and II section PT switch are opened or closure, warning simultaneously simultaneously.