CN103399243A - Cable defect simulation model - Google Patents

Abstract

The invention relates to a cable defect simulation model, which includes a simulation model with one suspended end and a simulation model with two suspended ends, wherein the simulation model with one suspended end is used for simulating the conditions of single transposition box or a damaged grounded box and sequentially disconnected and crossed interconnection boxes and grounded boxes; the simulation model with two suspended ends is used for simulating the conditions of adjacent two or more transposition boxes or damaged grounded boxes and an intact cable over sheath. Compared with the prior art, the cable defect simulation model has the advantages that the site detection efficiency and detection accuracy are effectively improved, and the like.

Description

A kind of electric cable stoppage realistic model

Technical field

The present invention relates to a kind of cables simulation technology, especially relate to a kind of electric cable stoppage realistic model.

Background technology

The mode that the District of Shanghai high-tension cable mainly takes comb to lay, middle transposition case and grounding box all adopt the fiberglass double door console mode of Uniting, mostly are arranged on work well neighbouring walkway, greenery patches.Adopt transposition case, the grounding box of ground vertical, the convenient advantage of installing, moving, overhauling and detect is arranged, but also easily destroyed simultaneously.Shanghai Power Network 110kV and above cable sheath earthed system defect main Types are divided into: the municipal works transformation; Outside destroy; Steal; Operational defect.

By the defect number of times that 110kV in 2009,2010 and above cable sheath earthed system are occurred, add up result such as following table 1:

Table 1

1) municipal works transformation: due to the composite demand of urban development, town road need to be reconstructed and widen, so the transposition case that is placed on road surface needs displacement.In the shift operation process, need to cut-off concentric cable, temporarily destroy the cable sheath earthed system.

2) outside destroy: outside destroy is mainly the car hit case, and illegal excavation and barbarous construction cause earthed system to damage.Outside destroy is a significant problem of cable sheath earthed system defect always, and the outside destroy number of times of 09,10 year remains basically stable, and maintains a high level.

3) steal: the annex because the cable sheath earthed system adopts, as concentric cable, transposition (ground connection) row etc., be copper product, price is high.In these 2 years, steal phenomenon all occurs in the region, Songjiang, and area of living in is comparatively remote bleak and desolate, as SS1167/1169.Although it is larger that the pilferage situation accounts for the proportion of all defects count, and the earthed system damaged condition that pilferage causes is very serious, even also encounters three continuous shifting sections and all destroys, the operation of serious harm cable body.Earthed system after stealing is carried out to the repair difficulty large, hot line job jeopardizes staff's life security, also lacks correlation experience and concrete rules, can only adopt power failure operation.

4) operational defect: the defect of finding in routine test, needs to change lower than setting such as the sheath protector insulation resistance; Perhaps stake resistance is excessive, reinstall ground connection etc.

Therefore how the defect of cable system is carried out to emulation, and by emulation, carry out the type of further analyzing defect, thereby further improve overhaul efficiency and prevent that defect from occurring.

Summary of the invention

Purpose of the present invention is exactly to provide a kind of electric cable stoppage realistic model for the defect that overcomes above-mentioned prior art existence.

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

A kind of electric cable stoppage realistic model, it is characterized in that, comprise an end suspension realistic model and two ends suspension realistic model, wherein an end suspension realistic model is for the single transposition case of emulation or grounding box is destroyed and disconnect successively cross interconnected case and the grounding box situation, and suspension realistic model in two ends is for adjacent two places of emulation and above transposition case or grounding box damages and the oversheath fine status of cable.

A described end suspension realistic model comprises the cable body that multistage is connected successively, between the adjacent segment cable body, be serially connected with concentric cable in twos, on first paragraph cable body and final stage cable body, all be connected to grounding box, wherein all the other concentric cable two ends all are parallel with the transposition case except the concentric cable that has fault location.

The described concentric cable two ends of fault location that exist are provided with the first voltage table and second voltage table, and the described adjacent concentric cable of the concentric cable of fault location that exists is provided with the tertiary voltage table.

The input signal of a described end suspension realistic model comprises normal run signal, lightning surge signal and switching overvoltage signal.

Described two ends suspension realistic model is specially: look conductor shielding and insulation shielding, protective metal shell and ground and form the coaxial cylindrical electric capacity that two capacitances are respectively C1, C2.

Compared with prior art, the present invention has the multiple electric cable stoppage of emulation, has set up the database of electric cable stoppage type and induced voltage, for Site Detection provides the data basis, thereby has effectively improved Site Detection efficiency and accuracy of detection.

The accompanying drawing explanation

Fig. 1 is that input signal is an end suspension realistic model schematic diagram of normal run signal;

Fig. 2 is that input signal is an end suspension realistic model schematic diagram of lightning surge signal;

Fig. 3 is that input signal is an end suspension realistic model schematic diagram of switching overvoltage signal;

Fig. 4 is two ends suspension realistic model schematic diagram;

The first voltage table induced voltage curve map when Fig. 5 is the lightning surge signal;

Second voltage table induced voltage curve map when Fig. 6 is the lightning surge signal;

The first voltage table induced voltage curve map when Fig. 7 is the switching overvoltage signal;

Second voltage table induced voltage curve map when Fig. 8 is the switching overvoltage signal.

Embodiment

The present invention is described in detail below in conjunction with the drawings and specific embodiments.

Embodiment

A kind of electric cable stoppage realistic model, comprise an end suspension realistic model and two ends suspension realistic model, wherein an end suspension realistic model is for the single transposition case of emulation or grounding box is destroyed and disconnect successively cross interconnected case and the grounding box situation, and suspension realistic model in two ends is for adjacent two places of emulation and above transposition case or grounding box damages and the oversheath fine status of cable.

As Figure 1-3, a described end suspension realistic model comprises the cable body 1 that multistage is connected successively, 1 of adjacent segment cable body is serially connected with concentric cable 2 in twos, on first paragraph cable body 1 and final stage cable body 1, all be connected to grounding box 4, wherein all the other concentric cable two ends all are parallel with transposition case 3 except the concentric cable that has fault location.

The described concentric cable two ends of fault location that exist are provided with the first voltage table 5 and second voltage table 6, and the described adjacent concentric cable of the concentric cable of fault location that exists is provided with tertiary voltage table 7.

The input signal of a described end suspension realistic model comprises normal run signal, lightning surge signal and switching overvoltage signal.

One, normal run signal:

It is the cable of 800mm2 that cable adopts the 110kV cross section, and current-carrying capacity of cable is 800A, and the measurement data of the first voltage table 5, second voltage table 6 and tertiary voltage table 7 is as shown in table 2.

Table 2

From table 2, can find out, during displacement, causing mode single-end earthed is not very serious on the impact of the induced voltage of metallic sheath.

As can be seen from Table 2, as shown in table 3 in the potential difference (PD) relation of the concentric cable left end of fault location and right-hand member.

Table 3

?	The A phase	The B phase	The C phase	A-C	B-A	C-B
							Potential difference (PD) (V)	4.2	18.7	26	34.2	20.6	10.5

Two, lightning surge signal

When lightning surge, as shown in Figure 2, the induction voltage waveform of the first voltage table and second voltage table as illustrated in Figures 5 and 6 for realistic model.

From figure, drawing, the maximal value at the first voltage table place is: A (331.5kV), B (336.2kV), C (321.7kV); The maximal value at second voltage table place is: A (382.1kV), B (369.2kV), C (298.7kV).

The potential difference (PD) relation is as shown in table 4.

Table 4

?	The A phase	The B phase	The C phase	A-C	B-A	C-B
							Potential difference (PD) (kV)	50.6	33	23	32.8	45.9	47.5

Three, switching overvoltage signal

When switching overvoltage, as shown in Figure 3, the induction voltage waveform of the first voltage table and second voltage table as shown in FIG. 7 and 8 for realistic model.

In figure, can find out, during switching overvoltage, the maximal value at the first voltage table place is: A (151.5kV), B (157.3kV), C (164.9kV); The maximal value at second voltage table place is: A (189.6kV), B (199.6kV), C (212.0kV).

The potential difference (PD) relation is as shown in table 5.

Table 5

?	The A phase	The B phase	The C phase	A-C	B-A	C-B
							Potential difference (PD) (kV)	38.1	42.3	47.1	60.5	32.3	34.7

As shown in Figure 4, described two ends suspension realistic model is specially: look conductor shielding and insulation shielding, protective metal shell and ground and form the coaxial cylindrical electric capacity that two capacitances are respectively C1, C2.This is a kind of cable a kind of voltage distribution situation radially, and the electric current that cable conductor flows through also can produce induced voltage on metallic sheath, but this voltage compares with the radially-arranged voltage of cable, with regard to little a lot, can ignore.

Get XLPE relative dielectric constant ε _R1=2.3, the relative dielectric constant ε of oversheath insulation _R2=3.5, suppose the intact and abundant ground connection of external electrode, but brief calculation goes out metal sheath voltage-to-ground Us:

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=2\mathrm{\&pi;}\&times;{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">r</figure-callout>}1}\&times;{\mathrm{\&epsiv;}}_0\frac{l}{\ln \frac{R_2}{{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_1}}2\mathrm{\&pi;}\&times;2.3\&times;8.85\frac{l}{\ln \frac{32.9}{15}}$

$=163l\left(\mathrm{pF}\right)$

${\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_2=2\mathrm{\&pi;}\&times;{\mathrm{\&epsiv;}}_{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">r</figure-callout>}2}\&times;{\mathrm{\&epsiv;}}_0\frac{l}{\ln \frac{R_4}{{\mathrm{<figure-callout\; id="3"\; label="R"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_3}}=2\mathrm{\&pi;}\&times;3.5\&times;8.85\frac{l}{\ln \frac{48.65}{43.75}}$

$=1832l\left(\mathrm{pF}\right)$

$U_s=\frac{C_1}{{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="2013103592459100003DEST\_PATH\_IMAGE001.png,HDA0000367907410000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2}{\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA0000367907410000022.png,HDA0000367907410000023.png"\; state="\{\{state\}\}">U</figure-callout>}}_0=\frac{163l}{163l+1832l}\&times;64\&times;{10}^3$

$=5229\left(V\right)$

In following formula, for the 110kV cross section, be the metallic sheath voltage over the ground of the cable of 630mm2.

In like manner, can calculate the voltage in other cross sections of 110kV and the metallic sheath voltage over the ground of 220kV cable, as shown in table 6.

Table 6

It doesn't matter for inductive voltage value when metallic sheath suspends fully and the length of cable.

Claims (5)

1. electric cable stoppage realistic model, it is characterized in that, comprise an end suspension realistic model and two ends suspension realistic model, wherein an end suspension realistic model is for the single transposition case of emulation or grounding box is destroyed and disconnect successively cross interconnected case and the grounding box situation, and suspension realistic model in two ends is for adjacent two places of emulation and above transposition case or grounding box damages and the oversheath fine status of cable.

2. a kind of electric cable stoppage realistic model according to claim 1, it is characterized in that, a described end suspension realistic model comprises the cable body that multistage is connected successively, between the adjacent segment cable body, be serially connected with concentric cable in twos, on first paragraph cable body and final stage cable body, all be connected to grounding box, wherein all the other concentric cable two ends all are parallel with the transposition case except the concentric cable that has fault location.

3. a kind of electric cable stoppage realistic model according to claim 2, it is characterized in that, the described concentric cable two ends of fault location that exist are provided with the first voltage table and second voltage table, and the described adjacent concentric cable of the concentric cable of fault location that exists is provided with the tertiary voltage table.

4. a kind of electric cable stoppage realistic model according to claim 3, is characterized in that, the input signal of a described end suspension realistic model comprises normal run signal, lightning surge signal and switching overvoltage signal.

5. a kind of electric cable stoppage realistic model according to claim 1, is characterized in that, described two ends suspension realistic model is specially: look conductor shielding and insulation shielding, protective metal shell and ground and form the coaxial cylindrical electric capacity that two capacitances are respectively C1, C2.

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