CN104198876A - Neutral-line disconnection detecting and positioning device and method for low-voltage system - Google Patents
Neutral-line disconnection detecting and positioning device and method for low-voltage system Download PDFInfo
- Publication number
- CN104198876A CN104198876A CN201410474311.1A CN201410474311A CN104198876A CN 104198876 A CN104198876 A CN 104198876A CN 201410474311 A CN201410474311 A CN 201410474311A CN 104198876 A CN104198876 A CN 104198876A
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- point positioning
- break point
- criterion
- neutral line
- positioning unit
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Abstract
The invention relates to a neutral-line disconnection detecting and positioning device and method for a low-voltage system. The neutral-line disconnection detecting and positioning device is characterized by comprising a direct-current voltage source, a plurality of disconnection point positioning units and a judgment information sampling resistor, wherein the first disconnection point positioning unit is next to user load and serially connected with the direct-current voltage source and the judgment information sampling resistor and bridged on a three-phase four-wire system power supply circuit, and other disconnection point positioning units are uniformly mounted on the three-phase four-wire system power supply circuit between a secondary side leading-out terminal of a power supply transformer and the first disconnection point positioning unit. By the method, disconnection or not of neutral lines can be judged and locations of the disconnection points can be determined according to measured actual voltage value of the judgment information sampling resistor, great convenience is provided for quick maintenance after failure occurrence, and the neutral-line disconnection detecting and positioning device has the advantages of accuracy, reliability, feasibility, low cost and the like.
Description
Technical field
The invention belongs to low-pressure system and detect resist technology field, especially a kind of low-pressure system broken neutral line detects and broken string locating device and method.
Background technology
In three phase and four wire circuit system, the entirety of the neutral line and a practicability and effectiveness of three phase line formations.The existence of the neutral line, makes three-phase voltage keep balance and stability, can not occur because of the imbalance of three-phase load excessive neutral point excursion, even certain phase line fuse failure, other two phase loads still can be worked under normal voltage.But, if broken neutral line, become large by making by the load unbalanced neutral point potential shift causing, three-phase voltage can not keep balance, load side each phase voltage compared with normal overtension or too low, the phase of overtension may be burnt consumer, and the phase of brownout may make consumer cisco unity malfunction, and user is caused to very large economic loss.
At present, exist a large amount of unpredictable broken neutral line accidents in low-voltage power supply system, concrete reason comprises Harmonic overloading, steals line, construction etc., therefore, is badly in need of the device whether automatic fast detecting neutral line of a kind of energy breaks and determine broken string position.Existing Busch lemniscate yarn cutting testing apparatus all can only be made broken neutral line whether detection mostly, can not realize broken string location positioning simultaneously, and this is that the maintenance occurring after disconnection fault has brought trouble.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, provide a kind of low-pressure system broken neutral line to detect and broken string locating device and method, can effectively detect the broken neutral line fault in three phase and four wire circuit system and realize break point positioning function, for the Quick overhaul after fault generation provides great convenience.
The present invention solves its technical matters and takes following technical scheme to realize:
A kind of low-pressure system broken neutral line detects and broken string locating device, comprise direct voltage source, multiple break point positioning unit and criterion intelligence sample resistance, the adjacent user load of first break point positioning unit, this break point positioning unit is connected with direct voltage source, criterion intelligence sample resistance, A, B, C tri-ends of this break point positioning unit are connected with three phase lines of three-phase four-wire power supply circuit respectively, N end is connected with direct voltage source one end, criterion intelligence sample resistance one end is connected with the direct voltage source other end, and the other end is connected with neutral line N; Other break point positioning units are uniform to be arranged between supply transformer secondary side leading-out terminal and first break point positioning unit and the neutral line is divided into multistage, its mounting means is: break point positioning unit A, B, C tri-ends are connected on respectively in three phase lines of three-phase four-wire power supply circuit, and N end is connected on the neutral line.
And described break point positioning unit is made up of three groups of RLC resonant circuits, wherein inductance L is connected with resistance R with after capacitor C parallel connection again.
A kind of low-pressure system broken neutral line detects and broken string localization method, comprises the following steps:
Step 1, direct voltage source, multiple break point positioning unit and criterion intelligence sample resistance are installed in three-phase four-wire power supply circuit;
Step 2, set up the ohmically magnitude of voltage computation model of criterion intelligence sample according to equivalent electrical circuit; Calculate the ohmically theoretical voltage value of criterion intelligence sample of different interval broken neutral lines; Measure the ohmically actual voltage value of criterion intelligence sample, compare according to actual voltage value and theoretical voltage value, judged whether broken neutral line and determined broken string position.
Advantage of the present invention and good effect are:
The present invention is reasonable in design, whether its needs can judge broken neutral line and definite break point position according to the ohmically magnitude of voltage of criterion intelligence sample, realize the broken neutral line point location function in three phase and four wire circuit system, for the Quick overhaul of fault after occurring provides great convenience, have accurately and reliably, be easy to realize, the feature such as with low cost.
Brief description of the drawings
Fig. 1 is the wiring diagram that the present invention is applied to three phase and four wire circuit system;
Fig. 2 is the circuit diagram of break point positioning unit;
Fig. 3 is the equivalent circuit diagram of broken neutral line detection of the present invention and break point positioning principle.
Embodiment
Below in conjunction with accompanying drawing, the embodiment of the present invention is further described:
A kind of low-pressure system broken neutral line detects and broken string locating device, as shown in Figure 1, comprises direct voltage source 1, multiple break point positioning unit 2 and criterion intelligence sample resistance 3, and described direct voltage source is that current supply circuit injects direct current detection signal; Described break point positioning unit, for direct current detection signal provides path, has the effect of blocking-up alternating current simultaneously, makes its impact on electrical network normal power supply very little; Described criterion intelligence sample resistance is used for gathering information of voltage, and information has judged whether broken neutral line and broken string position thus, thus the testing result of obtaining.The concrete annexation of described direct voltage source, break point positioning unit and criterion intelligence sample resistance is:
The adjacent user load of first break point positioning unit, this break point positioning unit is connected with direct voltage source, criterion intelligence sample resistance, A, B, C tri-ends of this break point positioning unit are connected with three phase lines of three-phase four-wire power supply circuit respectively, N end is connected with direct voltage source one end, criterion intelligence sample resistance one end is connected with the direct voltage source other end, and the other end is connected with neutral line N; Other break point positioning units are uniform to be arranged between supply transformer secondary side leading-out terminal and first break point positioning unit and the neutral line is divided into multistage, its mounting means is: break point positioning unit A, B, C tri-ends are connected on respectively in three phase lines of three-phase four-wire power supply circuit, and N end is connected on the neutral line.
As shown in Figure 2, described break point positioning unit is made up of three groups of RLC resonant circuits, and wherein inductance L is connected with resistance R with after capacitor C parallel connection again, when
time, LC part in parallel is parallel resonance state to the alternating current of 50Hz, equiva lent impedance is infinitely great, has played the effect that blocking-up exchanges; And now every group of series resonant network to direct current detection signal, impedance is R, thereby realized, mains supply itself is not exerted an influence, simultaneously for direct current detection signal provides path.
The detection principle of the detection of this low-pressure system broken neutral line and broken string locating device is as follows:
Direct voltage source sends DC voltage detection signal, one group of break point positioning unit, phase line, other break point positioning units and Circuit Fault on Secondary Transformer, user load (three's relation in parallel), the neutral line and criterion intelligence sample resistance by connecting with it form loop, the criterion intelligence sample resistance dividing potential drop of connecting with other parts of loop.The neutral line is without when broken string, Circuit Fault on Secondary Transformer winding is with to be all directly connected across break point positioning unit between phase line and zero line in parallel, because the impedance concerning direct current detection signal of Circuit Fault on Secondary Transformer winding is very little, can think that transformer secondary winding is substantially by the break point positioning unit short circuit in parallel with it, only one group of break point positioning unit and the transformer secondary winding dividing potential drop of connecting with criterion intelligence sample resistance, the voltage major part of direct voltage source drops on criterion intelligence sample resistance.In the time that the neutral line has broken string, due to broken neutral line position difference, can form the break point positioning unit number difference in parallel in loop, the equivalent resistance size of therefore connecting with criterion intelligence sample resistance changes with the variation of broken neutral line position, break point more approaches small-signal injector, the quantity of break point positioning unit in parallel that can form loop is just fewer, the equivalent resistance resistance of the part of connecting with criterion intelligence sample resistance is larger, and the voltage of therefore getting on criterion intelligence sample resistance is less; Until when the adjacent criterion intelligence sample of break point resistance, only have user load and the one group break point positioning unit source-series with DC voltage to connect with criterion intelligence sample resistance, the equivalent resistance resistance of the part of now connecting with criterion intelligence sample resistance is larger, and the voltage of getting on criterion intelligence sample resistance only accounts for the sub-fraction of direct voltage source.
In sum, in the time that the neutral line has or not broken string and broken string position difference, the ohmically magnitude of voltage of criterion intelligence sample varies in size, and various broken string situations are corresponding one by one with criterion intelligence sample resistive voltage, therefore, can judge according to the size of voltage on criterion intelligence sample resistance whether the neutral line breaks and break position.
A kind of low-pressure system broken neutral line detects and broken string localization method, comprises the following steps:
Step 1, according to shown in Fig. 1, by low-pressure system broken neutral line detect and broken string locating device be installed in three-phase four-wire power supply circuit.
Step 2, set up criterion intelligence sample resistance R according to equivalent electrical circuit
zon magnitude of voltage computation model; Calculate the criterion intelligence sample resistance R of different interval broken neutral lines
zon theoretical voltage value; Measure criterion intelligence sample resistance R
zon actual voltage value, compare according to actual voltage value and theoretical voltage value, judged whether broken neutral line and determine broken string position.
The equivalent circuit diagram of this detection method as shown in Figure 3.The present embodiment describes as an example of four break point positioning units example, and 1., 2., 3., 4. four break point positioning units are divided into four intervals by circuit, E
sfor direct voltage source, R
zfor criterion intelligence sample resistance, R
d1, R
d2, R
d3, R
d4for the equivalent resistance of break point positioning unit to direct current detection signal, resistance equates.R
nfor user load equivalent resistance, R
sfor Circuit Fault on Secondary Transformer winding equivalent resistance.The actual conditions of considering three phase and four wire circuit system, line resistance can be ignored.When line neutral is without when broken string, due to Circuit Fault on Secondary Transformer winding equivalent resistance R
svery little, can think R
sby the R in parallel with it
d1, R
d2, R
d3and R
nshort circuit, in the case R
zon magnitude of voltage
when in circuit when interval 1 interior broken neutral line, R
sopen circuit, left side circuit is the parallel connection of 3 groups of break point positioning units, now with R
zseries connection part equivalent resistance becomes
sampling resistor R
zon the voltage got be
due to R
f1>R
d4, V during with respect to nothing broken string
z1<V
z0; With should interval 2 interior broken neutral line time, R
1open circuit, left side circuit is 2 groups of break point location resistance parallel connections, now with R
zseries connection part equivalent resistance becomes
sampling resistor R
zon the voltage got be
due to R
f2>R
f1, V when interior in interval 1 with respect to break point
z2<V
z1; In the time of interval 3 interior broken neutral line, R
2open circuit, left side circuit is 1 group of break point location resistance, now with R
zseries connection part equivalent resistance becomes R
f3≈ (R
d3|| R
n)+R
d4, sampling resistor R
zon the voltage got be
due to R
f3>R
f2, V when interior in interval 2 with respect to break point
z3<V
z2; In the time that break point is interior in interval 4, R
zwith R
d4, R
nseries connection dividing potential drop, now
because R
d4+ R
n>R
f3, therefore V
z4<V
z3.Hence one can see that, and the disconnected and break point of the neutral line is respectively interval 1,2,3,4 when interior, and the ohmically magnitude of voltage computation model of criterion intelligence sample is as shown in table 1.
Criterion intelligence sample resistance R in the various broken string situations of table 1
zon magnitude of voltage computation model
Due in difference broken string situation with R
zseries connection part equivalent resistance difference, its pass is R
d4<R
f1<R
f2<R
f3<R
d4+ R
n, therefore on each situation down-sampling resistance, voltage relationship is V
z0>V
z1>V
z2>V
z3>V
z4.Thus can be by detecting R
zon the magnitude of voltage got just can determine broken neutral line point position.
Table 2 has provided an application testing result of the present invention.Wherein, in Fig. 3, in equivalent electrical circuit, each element value is as follows: break point positioning unit equivalent resistance R
d1=R
d2=R
d3=R
d4=1 Ω, Circuit Fault on Secondary Transformer equivalent resistance R
s=0.1 Ω, criterion intelligence sample resistance R
z=3 Ω, load equivalent resistance R
n=6 Ω, direct voltage source E
s=5V.Now in different broken string situations, the ohmically magnitude of voltage of criterion intelligence sample is as shown in table 2, can find out that the ohmically magnitude of voltage of criterion intelligence sample has obvious difference in difference broken string situation, can judge neutral line note situation and broken string position in three phase and four wire circuit system as criterion.
Various broken string situation down-sampling resistance R in table 2 concrete application
zon magnitude of voltage
| Broken string situation | Sampling resistor R zMagnitude of voltage |
| Without broken string | V z0≈3.68V |
| Interval 1 broken string | V z1≈3.47V |
| Interval 2 broken strings | V z2≈3.36V |
| Interval 3 broken strings | V z3≈3.09V |
| Interval 4 broken strings | V z4≈1.50V |
Above-mentioned is the explanation that a kind of situation there to be 3 groups of break point positioning units between Circuit Fault on Secondary Transformer and direct voltage source is made, and it should be noted that the method stands good in the time that the break point positioning unit of other suitable quantities is set on circuit.
In addition, consider the impact that user load changes, because sampling resistor, break point positioning unit equivalent resistance are all very little, pull-up resistor is subject to the restriction of maximum carrying load ability, load equivalent resistance has certain lower limit, and therefore the variation of certain limit internal burden is very little on the impact of criterion intelligence sample resistive voltage.
It is emphasized that; embodiment of the present invention is illustrative; instead of determinate; therefore the present invention includes and be not limited to the embodiment described in embodiment; every other embodiments that drawn by those skilled in the art's technical scheme according to the present invention, belong to the scope of protection of the invention equally.
Claims (3)
1. a low-pressure system broken neutral line detects and broken string locating device, it is characterized in that: comprise direct voltage source, multiple break point positioning units and criterion intelligence sample resistance, the adjacent user load of first break point positioning unit, this break point positioning unit and direct voltage source, the series connection of criterion intelligence sample resistance, the A of this break point positioning unit, B, C tri-ends are connected with three phase lines of three-phase four-wire power supply circuit respectively, N end is connected with direct voltage source one end, criterion intelligence sample resistance one end is connected with the direct voltage source other end, the other end is connected with neutral line N, other break point positioning units are uniform to be arranged between supply transformer secondary side leading-out terminal and first break point positioning unit and the neutral line is divided into multistage, its mounting means is: break point positioning unit A, B, C tri-ends are connected on respectively in three phase lines of three-phase four-wire power supply circuit, and N end is connected on the neutral line.
2. a kind of low-pressure system broken neutral line according to claim 1 detects and broken string locating device, it is characterized in that: described break point positioning unit is made up of three groups of RLC resonant circuits, and wherein inductance L is connected with resistance R with after capacitor C parallel connection again.
3. as the low-pressure system broken neutral line of claim 1 or 2 detects and an implementation method for broken string locating device, comprise the following steps:
Step 1, direct voltage source, multiple break point positioning unit and criterion intelligence sample resistance are installed in three-phase four-wire power supply circuit;
Step 2, set up the ohmically magnitude of voltage computation model of criterion intelligence sample according to equivalent electrical circuit; Calculate the ohmically theoretical voltage value of criterion intelligence sample of different interval broken neutral lines; Measure the ohmically actual voltage value of criterion intelligence sample, compare according to actual voltage value and theoretical voltage value, judged whether broken neutral line and determined broken string position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410474311.1A CN104198876B (en) | 2014-09-17 | 2014-09-17 | Neutral-line disconnection detecting and positioning device and method for low-voltage system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410474311.1A CN104198876B (en) | 2014-09-17 | 2014-09-17 | Neutral-line disconnection detecting and positioning device and method for low-voltage system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104198876A true CN104198876A (en) | 2014-12-10 |
| CN104198876B CN104198876B (en) | 2017-01-25 |
Family
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|---|---|---|---|
| CN201410474311.1A Expired - Fee Related CN104198876B (en) | 2014-09-17 | 2014-09-17 | Neutral-line disconnection detecting and positioning device and method for low-voltage system |
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Cited By (10)
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| CN107040283A (en) * | 2016-02-04 | 2017-08-11 | 杭州炬华科技股份有限公司 | One kind is based on power carrier data transmission circuit |
| CN107607858A (en) * | 2017-09-22 | 2018-01-19 | 信利光电股份有限公司 | Determination method, system, device and the readable storage medium storing program for executing of module open-circuit position |
| CN108008338A (en) * | 2017-11-13 | 2018-05-08 | 国网江西省电力有限公司电力科学研究院 | A kind of non-effective access automatic identifying method of the electric energy meter neutral conductor |
| CN105759164B (en) * | 2016-04-05 | 2018-05-15 | 国网江西省电力科学研究院 | A kind of broken neutral line detecting and localization method |
| CN108051696A (en) * | 2017-12-11 | 2018-05-18 | 李玉诚 | A kind of detection method for detection device connection status |
| CN109061394A (en) * | 2018-09-14 | 2018-12-21 | 国网江苏省电力有限公司镇江供电分公司 | Null line breaking alarm positioning device and method |
| CN111337852A (en) * | 2020-03-27 | 2020-06-26 | 戴呈玲 | Distribution line fault detection method |
| CN112834977A (en) * | 2020-12-31 | 2021-05-25 | 宁波三星医疗电气股份有限公司 | Neutral line disconnection fault point detection and positioning method based on electric energy meter |
| CN113253153A (en) * | 2021-04-02 | 2021-08-13 | 中国南方电网有限责任公司超高压输电公司梧州局 | Neutral line abnormity judgment method based on non-fault phase second harmonic component ratio |
| CN114415066A (en) * | 2022-03-29 | 2022-04-29 | 菲尼克斯亚太电气（南京）有限公司 | Circuit system for detecting power failure and detection method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108008338A (en) * | 2017-11-13 | 2018-05-08 | 国网江西省电力有限公司电力科学研究院 | A kind of non-effective access automatic identifying method of the electric energy meter neutral conductor |
| CN108051696A (en) * | 2017-12-11 | 2018-05-18 | 李玉诚 | A kind of detection method for detection device connection status |
| CN109061394A (en) * | 2018-09-14 | 2018-12-21 | 国网江苏省电力有限公司镇江供电分公司 | Null line breaking alarm positioning device and method |
| CN109061394B (en) * | 2018-09-14 | 2023-10-13 | 国网江苏省电力有限公司镇江供电分公司 | Zero line breakage alarm positioning device and method for three-phase four-wire system power supply system |
| CN111337852A (en) * | 2020-03-27 | 2020-06-26 | 戴呈玲 | Distribution line fault detection method |
| CN112834977A (en) * | 2020-12-31 | 2021-05-25 | 宁波三星医疗电气股份有限公司 | Neutral line disconnection fault point detection and positioning method based on electric energy meter |
| CN112834977B (en) * | 2020-12-31 | 2022-04-26 | 宁波三星医疗电气股份有限公司 | Neutral line disconnection fault point detection and positioning method based on electric energy meter |
| CN113253153A (en) * | 2021-04-02 | 2021-08-13 | 中国南方电网有限责任公司超高压输电公司梧州局 | Neutral line abnormity judgment method based on non-fault phase second harmonic component ratio |
| CN114415066A (en) * | 2022-03-29 | 2022-04-29 | 菲尼克斯亚太电气（南京）有限公司 | Circuit system for detecting power failure and detection method thereof |
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