CN104753026A - Electricity leakage protecting system for preventing symmetric electricity leakage - Google Patents
Electricity leakage protecting system for preventing symmetric electricity leakage Download PDFInfo
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- CN104753026A CN104753026A CN201510118814.XA CN201510118814A CN104753026A CN 104753026 A CN104753026 A CN 104753026A CN 201510118814 A CN201510118814 A CN 201510118814A CN 104753026 A CN104753026 A CN 104753026A
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Abstract
The invention provides an electricity leakage protecting system for preventing symmetric electricity leakage. The system comprises a vacuum contactor, a controller, a three-phase electric reactor, a zero sequence voltage sensor, a current sensor, and a three-phase electric reactor connected with a power supply circuit of an electric device, wherein a neutral point is formed at the back of the three-phase electric reactor; the zero sequence voltage sensor is connected to the neutral point and electrically connected with the controller through a controllable switch K2; a DC power supply, an additional resistor, the current sensor, and voltage sensors connected to two ends of the additional resistor are connected between the neutral point and the ground; a controllable switch k1 is connected between the current sensor on the DC circuit and the neutral point; the current sensor, the voltage sensors, the controllable switch k1 and the controllable switch k2 are electrically connected with the controller; the controller controls the on and off the vacuum contactor according to signals sensed by the zero sequence voltage sensor, the current sensor and the voltage sensor in order to control the on and off of the power supply of the electric device.
Description
Technical field
The present invention relates to a kind of leakage protection system, particularly relate to a kind of leakage protection system preventing symmetry from leaking electricity, belong to low pressure leakage protection field under ore deposit.
Background technology
Low-voltage leakage protection is the important protection of underground coal mine electric power system; and existing earth leakage protective misjudgment phenomenon is serious; branch road electric leakage usually causes master switch overstep tripping; not only cause large-area power-cuts; and owing to cutting off leakage time lengthening; damage equipment and cable, it is larger that the zero-sequence current produced safety of coal mines harmfulness and electric leakage jeopardizes degree to life.By the analysis to existing leakage protection system, can find to mainly contain two kinds of modes at present to detect leak resistance, and there is larger difference.
In prior art, a kind of leakage protection system adopts additional direct voltage method, and its cardinal principle forms neutral point by three-phase reactor, is connected in series a DC power supply and direct current sampling element between neutral point and ground.When system is leaked electricity, leakage, network transformer secondary circuit, reactor, DC power supply, between sampling resistor and ground, form loop.According to Ohm's law, the size of direct current directly reflects electrical network insulation against ground level (leak resistance).When leak resistance little to operating value (direct voltage that sampling resistor detects arrives operating value greatly) time, device and action.
The method detects leak resistance, and sample rate current and leak resistance are inversely proportional to, and its accuracy of detection is high.But due to the access of three-phase reactor, inductive current can not transition, and response speed is slow, reaching stable from generation electric leakage to electric current generally needs 200 more than ms.By the requirement of MT189-88 " flame-proof mine leak detection relay " standard, the operate time of master switch is 200 ms, and the operate time of branch switch is 30 ms.Obviously additional direct voltage method cannot meet the requirement of branch switch to operate time.
The another kind of leakage protection system of prior art adopts residual voltage method, and when electric leakage occurs isolated neutral system, neutral point voltage raises.During metallicity electric leakage, neutral point voltage is phase voltage.React leak resistance with residual voltage, residual voltage method that Here it is detects leak resistance, and it detects leak resistance fast response time, can meet the requirement of branch road earth leakage protective to operate time.But low-voltage leakage protection judges whether that the foundation of leaking electricity not is residual voltage, but leak resistance.Residual voltage is the multi-variable function about system voltage, system capacitance and leak resistance, not only relevant with leak resistance, but also is subject to the impact of system voltage and system capacitance.The reduction of Zero Sequence Voltage Versus leak resistance and increasing, can only react the trend that leak resistance affects residual voltage.
1) system voltage is on the impact of residual voltage: by MT189-88 standard-required, and line voltage is when 75% ~ 110% change of rated voltage, and leak resistance action error is not more than 20%.Residual voltage and system voltage are directly proportional, and when line voltage changes 75% ~ 110% of rated value, the metrical error of leak resistance can reach 25%, and the impact of system voltage on residual voltage is obvious.
2) system capacitance is on the impact of residual voltage: by MT189-88 standard-required, and when system capacitance changes within the scope of 0. 1 μ F ~ 1 μ F, action resistance error is not more than 20%.Table 1 is the residual voltage of 380 V systems and the relation (V is constant for line voltage 380, and the leak resistance operating value of 380 V systems is 3.5k Ω) of system capacitance C and leak resistance R.
Table 1-380V system zero sequence voltage and electric capacity, leak resistance relation
Found out by table 1 analysis, during same leak resistance, system capacitance increases, and residual voltage reduces; Same 3.5 k Ω ohmic leakages, during system capacitance 0.1 μ F and 1 μ F, nearly 150 V of residual voltage difference; When 30 k Ω leak electricity, residual voltage 73.2 V, this should action, as long as but system capacitance satisfy condition, between the active region that also can fall into 3.5 k Ω, cause malfunction.During same residual voltage 159.7 V, in the active region of 3.5 k Ω, should action, but tripping is caused under certain system capacitance.As can be seen here, the certainty of measurement detecting leak resistance by residual voltage method is very poor, does not reach the requirement that MT189-88 " flame-proof mine leak detection relay " standard specifies at all.
Therefore, residual voltage method exist subject matter be fail to judge and false determination ratio high, mainly because electric leakage accident is each time caused by different leaky site, therefore leak resistance also exists and varies.
For solving two kinds of method shortcomings, the present invention proposes the apparatus and method of use two kinds of method joint-detection electric leakages.
Summary of the invention
Scheme 1, a kind of leakage protection system preventing symmetry from leaking electricity, it is characterized in that, this system comprises: vacuum contactor, controller, three-phase reactor, residual voltage transducer, current sensor, the three-phase reactor be connected with power consumption equipment supply line, wherein, neutral point is formed after three-phase reactor, neutral point is connected with residual voltage transducer, voltage sensor is electrically connected with controller by gate-controlled switch K2, also DC power supply is connected between neutral point and ground, additional resistance and current sensor, the voltage sensor connected at additional resistance two ends, current sensor in DC circuit and be connected to gate-controlled switch k1 between neutral point, described current sensor and voltage sensor and gate-controlled switch k1 are electrically connected with controller with gate-controlled switch k2, controller is according to residual voltage sensor, the signal that current sensor and voltage sensor sensing come, the break-make of vacuum contactor is controlled thus controls the break-make of the power supply of power consumption equipment.
Scheme 2, the leakage protection system leaked electricity according to above-mentioned symmetry, power consumption equipment wherein can be multiple stage, and the signal that described sensing comes can carry out communication by the form of bus and controller.
Scheme 3, the leakage protection system of leaking electricity according to above-mentioned symmetry, described gate-controlled switch k1 wherein and gate-controlled switch k2 can not close simultaneously, or disconnects simultaneously.
Scheme 4, the leakage protection system of leaking electricity according to above-mentioned symmetry, it also comprises siren, when controller judges that the signal sensing occurs abnormal, alarm signal is sent to siren while cutting off power consumption equipment power supply, siren is reported to the police, and is shown on the display screen of controller by corresponding fault message.
Scheme 5, the present invention also discloses a kind of leakage protection method preventing symmetry from leaking electricity, it is characterized in that the voltage drop with the sampling resistor of additional direct voltage method detection system and electric current, and corresponding magnitude of voltage and current value are sent to controller, with the residual voltage of residual voltage method detection system, and residual voltage signal is sent to controller, the voltage drop of wherein said zero sequence voltage detection and DC circuit and current value measurement complete in different steps, and the measurement of the voltage drop of DC circuit and current value completed before zero sequence voltage detection, above-mentioned measured value and initial value compare by controller.
Scheme 6, according to above-mentioned method, if be wherein greater than at the current measurement value of DC circuit the sensing just carrying out residual voltage initial value is less than predetermined value.
Scheme 7, according to above-mentioned method, controller carries out break-make control with comparing of initial value to vacuum contactor according to the measured value of residual voltage.
Scheme 8, according to above-mentioned method, if when judging that residual voltage value does not change, the increment of the current value of DC circuit is measured while further disconnection zero sequence voltage detection circuit, if increment is greater than predetermined value, then controller is according to the signal cut vacuum contactor of current sensor, disconnects power consumption equipment power supply, and sends alarm signal to siren, siren is reported to the police, and is shown on the display screen of controller by corresponding fault message.
Scheme 9, method according to scheme 6, if wherein the current sense value of DC circuit is greater than initial value, and when the increment of the voltage measuring value at the two ends of additional resistance is also greater than predetermined value, controller directly controls vacuum contactor according to the measured value of DC circuit, cut off power consumption equipment power supply, send alarm signal to siren, siren is reported to the police, and is shown on the display screen of controller by corresponding fault message simultaneously.
Accompanying drawing explanation
Fig. 1 is leakage protection system schematic;
Fig. 2 is leakage protection working-flow figure.
Embodiment
Fig. 1 is the specific embodiment of the present invention, provides the detection of electrical leakage of two kinds of modes in FIG, is respectively residual voltage sensing and current sense.Power consumption equipment power input is by three reactor new city neutral points, then residual voltage sensing passes to controller by voltage transformer sensing neutral point voltage, DC power supply is connected between neutral point and ground, connecting path is connected to sample resistance, connect pressure drop sensor at sample resistance two ends, transducer passes to controller after detecting the pressure drop of sample resistance two ends.In addition, additional direct-voltage path is connected with sample resistance and is provided with current sensor, controller is passed to after electric current on sense current in direct path, controller controls to be connected with the vacuum contactor on power consumption equipment power bus road by control circuit, and controls to be connected with the gate-controlled switch K2 that the gate-controlled switch k1 in direct-voltage path and residual voltage sense on path.
Fig. 2 is leakage protection working-flow figure, and native system first to controller initialization, and checks the electricity condition of power consumption equipment at the beginning of work, and after confirmation enters electrical connection, system enters protection and checks operating state.First, closed k1, opens k2 and measures and record direct current and additional resistance pressure drop; Open the gate-controlled switch k1 in DC voltage circuit, measure and record residual voltage value.Second step, keep k1 to close, k2 opens, and detect direct current and additional resistance pressure drop at a certain time interval, and whether more described measured value is greater than initial value; If measured value is greater than initial value, enter the 3rd step, open k1, closed k2, detects residual voltage, compares residual voltage and whether be greater than initial value, if be greater than initial value to disconnect vacuum contactor cut-out power consumption equipment power supply, send alarm signal to siren, if residual voltage value is not more than initial value, so reenters second step and detect DC circuit electric current and magnitude of voltage.
In order to, increase practicality and the applicability of native system, wherein power consumption equipment can be multiple stage, and these sensing signals and control signal can be integrated into bus and be connected with controller by bus.
Claims (4)
1. the leakage protection system preventing symmetry from leaking electricity, it is characterized in that, this system comprises: vacuum contactor, controller, three-phase reactor, residual voltage transducer, current sensor, the three-phase reactor be connected with power consumption equipment supply line, wherein, neutral point is formed after three-phase reactor, neutral point is connected with residual voltage transducer, voltage sensor is electrically connected with controller by gate-controlled switch K2, also DC power supply is connected between neutral point and ground, additional resistance and current sensor, the voltage sensor connected at additional resistance two ends, current sensor in DC circuit and be connected to gate-controlled switch k1 between neutral point, described current sensor and voltage sensor and gate-controlled switch k1 are electrically connected with controller with gate-controlled switch k2, controller is according to residual voltage sensor, the signal that current sensor and voltage sensor sensing come, the break-make of vacuum contactor is controlled thus controls the break-make of the power supply of power consumption equipment.
2. the leakage protection system of the symmetry electric leakage of claim 1, power consumption equipment wherein can be multiple stage, and the signal that described sensing comes can carry out communication by the form of bus and controller.
3. the leakage protection system of symmetry electric leakage according to claim 1, described gate-controlled switch k1 wherein and gate-controlled switch k2 can not close simultaneously, or disconnects simultaneously.
4. according to the leakage protection system that the symmetry of any one of claim 1-3 is leaked electricity, it also comprises siren, when controller judges that the signal sensing occurs abnormal, alarm signal is sent to siren while cutting off power consumption equipment power supply, siren is reported to the police, and is shown on the display screen of controller by corresponding fault message.
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| CN201510118814.XA CN104753026A (en) | 2015-03-18 | 2015-03-18 | Electricity leakage protecting system for preventing symmetric electricity leakage |
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| CN201510118814.XA CN104753026A (en) | 2015-03-18 | 2015-03-18 | Electricity leakage protecting system for preventing symmetric electricity leakage |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105137876A (en) * | 2015-08-25 | 2015-12-09 | 孙鸿昌 | Industrial intelligent detection circuit control system |
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| CN102185296A (en) * | 2011-04-27 | 2011-09-14 | 江苏大学 | Selective electric leakage protection device and method for mine low-voltage power supply system |
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| CN203071654U (en) * | 2013-01-22 | 2013-07-17 | 山东能源电器股份有限公司 | Mine high-low voltage power grid leakage selection Ethernet ring network monitoring combined device |
| CN204167872U (en) * | 2014-11-25 | 2015-02-18 | 山西潞安环保能源开发股份有限公司常村煤矿 | Underground coal mine electrical network selective earth leakage protection checkout gear |
| CN204597454U (en) * | 2015-03-18 | 2015-08-26 | 胡妍 | A kind of leakage protection system preventing symmetry from leaking electricity |
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2015
- 2015-03-18 CN CN201510118814.XA patent/CN104753026A/en not_active Withdrawn
Patent Citations (5)
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| CN102185296A (en) * | 2011-04-27 | 2011-09-14 | 江苏大学 | Selective electric leakage protection device and method for mine low-voltage power supply system |
| CN202103403U (en) * | 2011-07-04 | 2012-01-04 | 山西兰花科技创业股份有限公司 | 630A mining flame-proof vacuum intelligent sub-feed switch |
| CN203071654U (en) * | 2013-01-22 | 2013-07-17 | 山东能源电器股份有限公司 | Mine high-low voltage power grid leakage selection Ethernet ring network monitoring combined device |
| CN204167872U (en) * | 2014-11-25 | 2015-02-18 | 山西潞安环保能源开发股份有限公司常村煤矿 | Underground coal mine electrical network selective earth leakage protection checkout gear |
| CN204597454U (en) * | 2015-03-18 | 2015-08-26 | 胡妍 | A kind of leakage protection system preventing symmetry from leaking electricity |
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| 贺鹏: "煤矿井下漏电保护技术研究", 《中国优秀硕士论文全文数据库》 * |
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Cited By (1)
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|---|---|---|---|---|
| CN105137876A (en) * | 2015-08-25 | 2015-12-09 | 孙鸿昌 | Industrial intelligent detection circuit control system |
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Application publication date: 20150701 |