CN103399259A - Input signal identification method based on single-end suspension simulation model - Google Patents

Abstract

The present invention relates to an input signal identification method based on a single-ended suspension simulation model. The single-ended suspension simulation model includes a plurality of sections of cable bodies connected in series in sequence, and coaxial cables are connected in series between two adjacent sections of the cable bodies. The first Both the cable body and the last cable body are connected with a grounding box, and except for the coaxial cable at the defect, the two ends of the other coaxial cables are connected in parallel with transposition boxes, and the two ends of the coaxial cable at the defect are A first voltmeter and a second voltmeter are provided, and the input signal identification method includes the following steps: 1) adding an excitation signal to the input end of the single-ended suspension simulation model; 2) the controller reads the first voltmeter and the voltmeter respectively. The induced voltage data of the second voltmeter is calculated to obtain the average induced voltage data; 3) the controller judges the type of the input signal according to the average induced voltage data. Compared with the prior art, the invention has the advantages of effectively improving on-site detection efficiency and detection accuracy.

Description

Input Signal Recognition Method Based on Single-Ended Suspension Simulation Model

technical field

The invention relates to a cable simulation technology, in particular to an input signal identification method based on a single-end suspension simulation model.

Background technique

The high-voltage cables in the Shanghai area are mainly laid by pipes. The intermediate transposition box and the grounding box are both floor-standing with unified design of glass fiber reinforced plastic double doors, and most of them are installed on the sidewalks and green areas near the wells. The ground vertical transposition box and grounding box have the advantages of convenient installation, operation, maintenance and testing, but they are also easy to be damaged. The main types of defects in the grounding system of 110kV and above cable sheaths in Shanghai Power Grid are divided into: municipal engineering transformation; external damage; theft; operation defects.

Through the statistics of the number of defects in the 110kV and above cable sheath grounding system in 2009 and 2010, the results are shown in Table 1:

Table 1

1) Municipal engineering renovation: due to the comprehensive needs of urban development, municipal roads need to be rebuilt and widened, so the transposition box placed on the road needs to be displaced. During the shifting operation, the coaxial cable needs to be disconnected to temporarily destroy the grounding system of the cable sheath.

2) External force damage: external force damage is mainly caused by car collision, illegal excavation and brutal construction, which cause damage to the grounding system. External force damage has always been a major problem of defects in the grounding system of the cable sheath. The number of external force damages in 2009 and 2010 was basically the same and maintained at a very high level.

3) Theft: Because the accessories used in the cable sheath grounding system, such as coaxial cables and transposition (grounding) bars, are all copper products, the price is high. In the past two years, all the thefts occurred in the Songjiang area, which is relatively remote and desolate, such as SS1167/1169. Although the theft accounts for a large proportion of the total number of defects, and the damage to the grounding system caused by theft is very serious, and even three consecutive transposition sections were all damaged, which seriously endangered the operation of the cable body. It is very difficult to repair the grounding system after the theft, and the live operation endangers the safety of the staff. There is also a lack of relevant experience and specific procedures, so power failure can only be used.

4) Defects in operation: Defects found in regular tests, such as the insulation resistance of the sheath protector is lower than the specified value and needs to be replaced; or the grounding resistance is too large and the grounding needs to be reinstalled, etc.

Therefore, how to effectively identify the input signal of the cable system, so as to further determine the cause of the defect, so as to further improve the maintenance efficiency and prevent the occurrence of defects.

Contents of the invention

The purpose of the present invention is to provide an input signal identification method based on a single-ended suspension simulation model in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

An input signal recognition method based on a single-ended suspension simulation model, the single-ended suspension simulation model includes a plurality of sections of cable bodies connected in series in sequence, coaxial cables are connected in series between two adjacent cable sections, and the first section of the cable body and the last section of the cable body are connected with a grounding box. Except for the coaxial cable at the defect, the two ends of the other coaxial cables are connected in parallel with transposition boxes. The two ends of the coaxial cable at the defect are provided with a second A voltmeter and a second voltmeter, characterized in that the input signal identification method comprises the following steps:

1) Add an excitation signal to the input end of the single-ended suspension simulation model;

2) The controller reads the induced voltage data of the first voltmeter and the second voltmeter respectively, and calculates the average induced voltage data;

3) The controller judges the type of the input signal according to the average induced voltage data.

The controller judges the type of the input signal according to the induced voltage data as follows:

31) If the average induced voltage data exceeds the set first threshold, it is judged that the input signal is a lightning overvoltage signal;

32) If the average induced voltage data is between the second threshold and the first threshold, it is judged that the input signal is an operation overvoltage signal;

33) If the average induced voltage data is lower than the second threshold, it is determined that the input signal is a normal operation signal.

If the cable adopts a 110kV cable with a section of 800mm ² , the first threshold is 230 to 280KV, and the second threshold is 100 to 150KV.

The first threshold is 250KV, and the second threshold is 130KV.

Compared with the prior art, the present invention has the ability to simulate various cable defects, establishes a database of cable defect types and induced voltages, and provides a data basis for on-site detection, thereby effectively improving on-site detection efficiency and detection accuracy.

Description of drawings

Fig. 1 is the schematic diagram of one end suspension simulation model of the present invention;

Fig. 2 is the curve diagram of the induced voltage of the first voltmeter during the lightning overvoltage signal;

Fig. 3 is the curve diagram of the induced voltage of the second voltmeter during the lightning overvoltage signal;

Fig. 4 is a curve diagram of the induced voltage of the first voltmeter when the overvoltage signal is operated;

Fig. 5 is a curve diagram of the induced voltage of the second voltmeter when the overvoltage signal is operated.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

An input signal recognition method based on a single-end suspension simulation model, as shown in Figure 1, the one-end suspension simulation model includes a plurality of sections of cable bodies 1 connected in series in sequence, and coaxial cables are connected in series between two adjacent sections of the cable body 1 The cable 2, the first section of the cable body 1 and the last section of the cable body 1 are all connected with a grounding box 4, and except for the coaxial cable with a defect, the two ends of the other coaxial cables are connected in parallel with a transposition box 3. A first voltmeter 5 and a second voltmeter 6 are provided at both ends of the coaxial cable at the defect.

The described input signal identification method comprises the following steps:

1) Add an excitation signal to the input end of the single-ended suspension simulation model;

2) The controller reads the induced voltage data of the first voltmeter and the second voltmeter respectively, and calculates the average induced voltage data;

3) The controller judges the type of the input signal according to the average induced voltage data.

The controller judges the type of the input signal according to the induced voltage data as follows:

31) If the average induced voltage data exceeds the set first threshold, it is judged that the input signal is a lightning overvoltage signal;

32) If the average induced voltage data is between the second threshold and the first threshold, it is judged that the input signal is an operation overvoltage signal;

33) If the average induced voltage data is lower than the second threshold, it is determined that the input signal is a normal operation signal.

If the cable adopts a 110kV cable with a section of 800mm ² , the first threshold is 250KV, and the second threshold is 130KV.

1. Normal operation signal:

The measurement data of the first voltmeter 5 and the second voltmeter 6 are shown in Table 2.

是很严重。

It's serious.

2. Lightning overvoltage signal

When lightning overvoltage occurs, the induced voltage waveforms of the first voltmeter and the second voltmeter are shown in Figures 2 and 3 .

From the figure, the maximum value at the first voltmeter is: A(331.5kV), B(336.2kV), C(321.7kV); the maximum value at the second voltmeter is: A(382.1kV), B (369.2kV), C (298.7kV).

3. Operating overvoltage signal

When operating overvoltage, the induced voltage waveforms of the first voltmeter and the second voltmeter are shown in FIGS. 4 and 5 .

It can be seen from the figure that when operating overvoltage, the maximum value at the first voltmeter is: A(151.5kV), B(157.3kV), C(164.9kV); the maximum value at the second voltmeter is: A (189.6kV), B (199.6kV), C (212.0kV).

Claims (4)

1. A kind of input signal recognition method based on single-ended suspension simulation model, described single-ended suspension simulation model comprises the cable body of multisection series connection successively, coaxial cable is connected in series between the cable body of two adjacent sections, the first section Both the cable body and the last section of the cable body are connected with a grounding box. Except for the coaxial cable at the defect, the two ends of the other coaxial cables are connected in parallel with transposition boxes. The two ends of the coaxial cable at the defect are set There are a first voltmeter and a second voltmeter, characterized in that the input signal identification method includes the following steps: 1) Add an excitation signal to the input end of the single-ended suspension simulation model; 2) The controller reads the induced voltage data of the first voltmeter and the second voltmeter respectively, and calculates the average induced voltage data; 3) The controller judges the type of the input signal according to the average induced voltage data. 2. a kind of input signal recognition method based on single-ended suspension simulation model according to claim 1, is characterized in that, described controller judges the type of input signal according to induced voltage data and is specifically: 31) If the average induced voltage data exceeds the set first threshold, it is judged that the input signal is a lightning overvoltage signal; 32) If the average induced voltage data is between the second threshold and the first threshold, it is judged that the input signal is an operation overvoltage signal; 33) If the average induced voltage data is lower than the second threshold, it is determined that the input signal is a normal operation signal. 3. a kind of input signal identification method based on single-ended suspension simulation model according to claim ² , it is characterized in that, if the cable adopts 110kV cross section is the cable of 800mm , described first threshold is 230 to 280KV, so The stated second threshold is 100 to 150KV. 4. The input signal recognition method based on a single-ended suspension simulation model according to claim 32, wherein the first threshold is 250KV, and the second threshold is 130KV.

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