CN106443396A - Online monitoring device for insulating performance of IT power supply system - Google Patents

Abstract

The invention relates to an online monitoring device for the insulating performance of an IT power supply system. The online monitoring device comprises a controller unit, an insulating signal sampling unit and a voltage sampling unit, wherein the insulating signal sampling unit comprises a first signal sampling branch, a second signal sampling branch and a sampling resistor, the first signal sampling branch comprises a first electronic switch, and the second signal sampling branch comprises a second electronic switch; the ground insulating signal of the IT system is acquired by turning on the first electronic switch and the second electronic switch through the controller unit. The online monitoring device has the advantages that the insulating performance of the IT power supply system can be monitored without an additional independent signal; the respective ground insulating resistance of two bus bars of the single-phase IT power supply system can be calculated accurately, short circuit faults can be monitored, and bus bar insulation deterioration degree can also be judged.

Description

IT electric power system insulating properties on-Line Monitor Device

Technical field

The present invention relates to a kind of Circuits System insulating properties monitoring device, especially a kind of IT electric power system insulating properties exist Line monitoring device.

Background technology

IT electric power system occurs that fault current during first time fault is little, and electrical equipment metal shell will not produce danger Contact voltage, therefore can not cut off the electricity supply, and so that electrical equipment is continued to run with, but needs to carry out on-line monitoring to its insulating properties And informed by warning device, check in time and eliminate fault.

In current IT electric power system insulating properties on-line monitoring, the widely used detection method based on Injection Signal, lead to Electric current on the voltage of sampling resistor or IT electric power system bus when crossing collection Injection Signal, when IT electric power system shorted to earth Or during insulation degradation, its insulation against ground resistance declines, the voltage on sampling resistor during Injection Signal or IT electric power system are female In electric current on line, fault characteristic value increases severely, and can be judged accordingly.When being insulated using injecting signal monitoring IT electric power system, No matter injection is direct current signal, single-frequency AC signal, or double frequency AC signal, it is required for corresponding independent signal source, is System is complicated；And the voltage effective value in independent signal source does not allow more than 50V, the judgement to fault characteristic value and failure line selection position Bring difficulty.

Content of the invention

In order to solve problem present in IT electric power system insulating properties on-line monitoring, the invention provides a kind of IT powers System insulation performance on-line monitoring device, including controller unit, insulating signal sampling unit, voltage sampling unit.

Described voltage sampling unit is used for obtaining bus ac voltage signal and delivering to controller unit；Described insulating signal Sampling unit is used for obtaining the insulation against ground signal of IT electric power system and delivering to controller unit.

Described insulating signal sampling unit includes the first sample of signal branch road, secondary signal sampling slip and sampling electricity Resistance；First sample of signal branch road includes the first electronic switch, the first current-limiting resistance being connected in series, the first electronic switch, first The order that is connected in series of current-limiting resistance arbitrarily selects；The second electronic switch that secondary signal sampling slip includes being connected in series, Two current-limiting resistances, the second electronic switch, the order that is connected in series of the second current-limiting resistance arbitrarily select；First sample of signal branch road One end connects to the first bus of IT electric power system, and one end of secondary signal sampling slip connects to the second mother of IT electric power system Line；The other end of the first sample of signal branch road, the other end of secondary signal sampling slip are connected with one end of sample resistance, The other end of sample resistance connects to protecting field.

The insulation against ground signal of described IT electric power system is the first bus burst pulse voltage, the second bus narrow arteries and veins over the ground over the ground Rush voltage, control the first electronic switch, the second electronic switch pulsed to open acquisition respectively by controller unit.

Described first electronic switch, the second electronic switch are interval in the peak value of the positive and negative half-wave of bus alternating voltage respectively Open-minded, or respectively in the peak value release of section of the negative, positive half-wave of bus alternating voltage.

Described first sample of signal branch road also includes the first diode connected, and described secondary signal sampling slip also includes Second diode of series connection；First diode makes the first electronic switch open-minded in bus alternating voltage a half-wave, the Two diodes make the second electronic switch open-minded in the another one half-wave of bus alternating voltage.

Described first sample of signal branch road also includes the 3rd diode, and described secondary signal sampling slip also includes the four or two Pole pipe；Described 3rd diode reverse is connected in parallel on the first electronic switch, and the 4th diode reverse is connected in parallel on the second electronic switch On.Diode reverse is connected in parallel on electronic switch, and the negative electrode referring to diode connects to the electric current inflow end of electronic switch, sun Pole connects to the electric current outflow end of electronic switch.

Described first electronic switch, the second electronic switch can also be respectively at the peaks of the different positive half-waves of bus alternating voltage Value release of section, or respectively in the peak value release of section of the negative half-wave of difference of bus alternating voltage.

First bus insulation against ground resistance R_F1, the second bus insulation against ground resistance R_F2According to formula

Calculated, wherein, R_EResistance value for the first current-limiting resistance and the second current-limiting resistance；R_SElectricity for sample resistance Resistance；U_mFor the peak value of bus alternating voltage, obtained according to the continuous sampling data of bus alternating voltage；U₁For the first electronic cutting Close the first bus burst pulse voltage over the ground when opening, U₂The burst pulse electricity over the ground of the second bus when opening for the second electronic switch Pressure.

Described U₁、U₂According to formula

Calculated, wherein, U_C1Sample resistance R when opening for the first electronic switch_SOn voltage, U_C2For the second electronic cutting Sample resistance R when pass is opened_SOn voltage.

Controller unit realizes the quality of power supply and the concrete steps of insulating properties monitoring include：

Step one, sampling obtain burst pulse voltage, the second bus burst pulse voltage and the bus friendship over the ground over the ground of the first bus Stream voltage data；

Step 2, calculating the first bus insulation against ground resistance and the second bus insulation against ground resistance；

Step 3, result treatment；

Step 4, return to step one.

Described IT electric power system insulating properties on-Line Monitor Device can also include alarm unit, man-machine interaction unit, school One of verification certificate unit unit or multiple unit.

The invention has the beneficial effects as follows：(1) additional independent signal need not be injected, you can realize the insulation to IT electric power system Performance monitoring；(2) insulating monitoring signal is direct current burst pulse voltage, can eliminate what bus direct-to-ground capacitance was monitored to insulaion resistance Impact；(3) the respective insulation against ground resistance value of single-phase 2 buses of IT electric power system can accurately be calculated, short except monitoring Additionally it is possible to judge the degree of bus insulation deterioration outside the fault of road.

Brief description

Fig. 1 is IT electric power system insulating properties on-Line Monitor Device embodiment composition frame chart；

Fig. 2 is insulating signal sampling unit embodiment circuit theory diagrams；

Equivalent circuit diagram when Fig. 3 opens for insulating signal sampling unit embodiment the first electronic switch；

Equivalent circuit diagram when Fig. 4 opens for insulating signal sampling unit embodiment the second electronic switch；

Fig. 5 is bus alternating voltage waveform and monitoring burst pulse V diagram.

Specific embodiment

Below in conjunction with accompanying drawing, the invention will be further described.

It is illustrated in figure 1 IT electric power system insulating properties on-Line Monitor Device embodiment composition frame chart.Fig. 1 embodiment includes Controller unit 100, insulating signal sampling unit 200, voltage sampling unit 300, verification unit 400, alarm unit 500, people Machine interactive unit 600.L1, L2 are respectively the first bus of IT electric power system, the second bus；PE is that the protection of IT electric power system is led Body or protecting field.Described IT electric power system is single-phase ac power supply system.

It is illustrated in figure 2 insulating signal sampling unit embodiment circuit theory diagrams, including the first electronic switch M1, the second electricity Son switch M2, the first current-limiting resistance R_E1, the second current-limiting resistance R_E2, sample resistance R_S, the first diode D1, the second diode D2, 3rd diode D3, the 4th diode D4；First electronic switch M1, the first current-limiting resistance R_E1, the first diode D1, the three or two pole Pipe D3 forms the first sample of signal branch road, the second electronic switch M2, the second current-limiting resistance R_E2, the second diode D2, the four or two pole Pipe D4 forms secondary signal sampling slip.In Fig. 2, R_F1、R_F2It is respectively the insulation against ground electricity of the first bus L1, the second bus L2 Resistance；K1, K2 are respectively the first electronic switch M1, the control signal of the second electronic switch M2, and K1, K2 are derived from controller unit.The One electronic switch, the second electronic switch are full-control type electronic switch, and in Fig. 2 embodiment, M1, M2 adopt triode type photoelectric coupling Device.First electronic switch, the second electronic switch can also be replaced with DC solid-state relay or other full-control type electronic switches Change.

In Fig. 2 embodiment, the 3rd diode D3, the 4th diode D4 protect the first electronic switch M1, the second electronics respectively Switch M2 is so as to exempt from too high backward voltage；When the first electronic switch, the second electronic switch can bear the anti-of place circuit During to voltage, the 3rd diode, the 4th diode are not necessarily.

In Fig. 2 embodiment, it can only be higher than second in the first bus L1 current potential that the first diode D1 makes the first electronic switch M1 Turn on during bus L2 current potential, the second diode D2 makes the second electronic switch M2 can only be less than the second bus in the first bus L1 current potential Turn on during L2 current potential；When the first electronic switch, the second electronic switch have one-way conduction performance and do not have the 3rd diode in parallel, During four diodes, the first diode, the second diode are not necessarily.

First electronic switch and the second electronic switch be the short time, pulsed open-minded, and the first electronic switch and Second electronic switch can not be opened simultaneously and turn on.It is higher than the second mother that first electronic switch can control in the first bus L1 current potential Open during line L2 current potential it is also possible to control open-minded when the first bus L1 current potential is less than the second bus L2 current potential；Similarly, second Electronic switch can control to be opened it is also possible to control in the first bus when the first bus L1 current potential is higher than the second bus L2 current potential L1 current potential is less than open-minded during the second bus L2 current potential.First electronic switch, the second electronic switch can be respectively in bus alternating currents The positive and negative half-wave of pressure is open-minded or open-minded in the negative, positive half-wave of bus alternating voltage respectively；First electronic switch, the second electricity Son switch can also be open-minded in the different positive half-waves of bus alternating voltage respectively, or respectively in the difference of bus alternating voltage Negative half-wave is open-minded.

Will be complete to the first diode D1 in Fig. 2 embodiment, the second diode D2, the 3rd diode D3, the 4th diode D4 Portion's Opposite direction connection, the first electronic switch M1, the sense of current Opposite direction connection of the second electronic switch M2, then the first diode D1 make One electronic switch M1 can only turn on when the first bus L1 current potential is less than the second bus L2 current potential, and the second diode D2 makes the second electricity Son switch M2 can only the conducting when the first bus L1 current potential is higher than the second bus L2 current potential.

It is illustrated in figure 3 equivalent circuit diagram when insulating signal sampling unit embodiment the first electronic switch is opened.

When first electronic switch M1 opens, the first bus L1 current potential is higher than the second bus L2 current potential, the voltage between L1, L2 For monitoring burst pulse voltage U_m.Make R₀=R_E1+R_S, R₄For R₀With R_F1Resistance value in parallel, then now the first bus burst pulse over the ground Voltage U₁For

Will

Substitution formula (1) simultaneously arranges, and has

It is illustrated in figure 4 equivalent circuit diagram when insulating signal sampling unit embodiment the second electronic switch is opened.Second When electronic switch M2 opens, the first bus L1 current potential is less than the second bus L2 current potential.Phase when the second electronic switch M2 opens Phase angle when parallactic angle is opened with the first electronic switch M1 is identical, and the monitoring burst pulse voltage between L2, L1 is U_m.When the first electricity The first bus that son switch, the second electronic switch are opened burst pulse voltage, the second bus burst pulse voltage position respectively over the ground over the ground When the peak value of 2 half-waves of bus alternating voltage is interval, U_mPeak value for bus alternating voltage.

Work as R_E2Resistance value be equal to R_E1Resistance value when, have R₀=R_E2+R_S, then now the second bus burst pulse voltage over the ground U₂For

According to formula (2) and formula (3), can obtain

Joint arrangement formula (2), formula (3), formula (4), have

Make the first current-limiting resistance R_E1With the second current-limiting resistance R_E2Resistance value be R_E, have

One of insulation against ground signal of IT electric power system, the first bus burst pulse voltage U over the ground₁By gathering the first electronics Sample resistance R when switch M1 opens_SOn voltage U_C1Obtain；The two of the insulation against ground signal of IT electric power system, the second bus pair Ground burst pulse voltage U₂Sample resistance R when being opened by gathering the second electronic switch M2_SOn voltage U_C2Obtain, and have

For limit the first electronic switch or when the second electronic switch opens the first bus or the second bus electricity over the ground Stream, the first current-limiting resistance R_E1With the second current-limiting resistance R_E2Resistance value be preferably greater than 500k Ω, particularly preferably be more than 2M Ω.

It is illustrated in figure 5 bus alternating voltage waveform and monitoring burst pulse V diagram.In Fig. 5, T₁For the first electronics The time that switch M1, the second electronic switch M2 postpone with respect to zero crossing, T₂For the first electronic switch M1, the second electronic switch M2 The time opened.If the cycle of bus alternating voltage is T, the moment opened as the first electronic switch M1, the second electronic switch M2 At the peak value of bus alternating voltage and T₂Sufficiently small, further, when

When, then the monitoring burst pulse voltage U between L2, L1 when the first electronic switch M1, the second electronic switch M2 open_mFor The crest voltage of bus alternating voltage.

First electronic switch M1 or the second electronic switch M2 service time T₂Short, now it is carried in the first bus and second Monitoring burst pulse voltage on the loop being formed between bus, by PE is the equal of direct current burst pulse voltage, because first is female Line, the second bus direct-to-ground capacitance little, to sample resistance R_SOn voltage when being sampled, it is right that direct current burst pulse voltage has completed The discharge and recharge of direct-to-ground capacitance, can avoid the first bus, the direct-to-ground capacitance of the second bus that insulating monitoring is impacted.

When the supply frequency of bus alternating voltage is high, its cycle T is little, for keeping the first electronic switch M1 or second electricity When son switch M2 opens, direct current burst pulse magnitude of voltage is basically unchanged, correspondingly, service time T₂Must be shorter.When bus alternating current When the supply frequency of pressure is less than 300Hz, keep the service time T that direct current burst pulse magnitude of voltage is basically unchanged₂Within, can be complete The in pairs discharge and recharge of direct-to-ground capacitance and to sample resistance R_SOn voltage sampled.

Voltage sampling unit is used for obtaining bus ac voltage signal and delivering to controller unit.The mistake of bus alternating voltage Zero point, peak value and cycle are obtained to the voltage continuous sampling data analysis of voltage sampling unit by controller unit.Controller list Unit needs control voltage sampling unit to carry out continuous sampling to bus alternating voltage.How design voltage sampling unit by control Device unit processed is realized carrying out continuous sampling to bus alternating voltage, and voltage continuous sampling data is analyzed obtaining bus The zero crossing of alternating voltage, peak value and cycle are the routine techniques that professional and technical personnel in the field are grasped.

When the insulation against ground of IT electric power system deteriorates or has shorted to earth fault, bus insulation against ground resistance is less than and sets Threshold resistance when, controller unit is reported to the police by alarm unit.Man-machine interaction unit be used for realizing the setting of threshold resistance, the One bus, the second bus insulation against ground resistance value such as show at the function.Carry out design the reality of alarm unit and man-machine interaction unit Existing required function is the routine techniques that professional and technical personnel in the field are grasped.

Verification unit is used for carrying out function check to the monitoring of described insulating properties.In embodiment illustrated in fig. 1, verification unit 400 are controlled by controller unit by man-machine interaction unit.Verification unit can also directly by man-machine interaction unit control, Directly it is controlled by switch, button.When carrying out function check, verification unit between the first bus and protecting field, or Between the second bus and protecting field, or simultaneously between the first bus and protecting field and the second bus and protecting field it Between access verification resistance, whether finder being capable of normal work.Directly by switch, button control in the first bus and protecting field Between, or between the second bus and protecting field, or simultaneously between the first bus and protecting field and the second bus Access verification resistance and protecting field between, and by man-machine interaction unit pass through controller unit be controlled in the first bus and Between protecting field, or between the second bus and protecting field, or simultaneously between the first bus and protecting field and Accessing verification resistance between two buses and protecting field is the routine techniques that professional and technical personnel in the field are grasped.

Controller unit includes the functional module such as MCU and A/D converter, signal conditioning circuit and circuit.Voltage sampling Unit output bus ac voltage signal, insulating signal sampling unit output insulation against ground signal through signal conditioning circuit at A/D converter is delivered to, A/D converter output data transfers to MCU process after reason.MCU is single with insulating signal sampling unit, verification Unit, alarm unit, man-machine interaction unit etc. have electrical connection, to carry out the information transmission of correlation.Control core MCU can select Select the microcontroller such as DSP, ARM, single-chip microcomputer, CPLD, PLC or control device.How to select and use A/D converter, and How modelled signal modulate circuit makes voltage sampling unit, the signal of insulating signal sampling unit output meet A/D converter pair The requirement of signal input, is the routine techniques that professional and technical personnel in the field are grasped.

The concrete steps that controller unit realizes single phase ac IT electric power system insulating monitoring include：

Step one, sampling obtain the voltage U of burst pulse over the ground of 2 half-waves of bus alternating voltage₁、U₂With bus alternating voltage Data；

Step 2, calculating obtain the first bus insulation against ground resistance R_F1With the second bus insulation against ground resistance R_F2；

Step 3, result show and alert process；

Step 4, return to step one.

In step one, sampling obtains the voltage U of burst pulse over the ground of 2 half-waves of bus alternating voltage₁、U₂When, can select to adopt With unitary sampling value it is also possible to select multiple repairing weld more multiple sampled values to be carried out including asking arithmetic mean of instantaneous value, median, slip Mean value, median mean value, or after the data processing of other modes, obtain end value.The peak value U of bus alternating voltage_m Can obtain according to the bus alternating voltage continuous sampling data of monocycle or multicycle.

Calculate in step 2 and obtain the first bus insulation against ground resistance R_F1With the second bus insulation against ground resistance R_F2, permissible Select using the first bus insulation against ground resistance R calculating acquisition after single execution step one and step 2_F1With the second bus pair Ground insulaion resistance R_F2It is also possible to selecting execution step one and step 2 are repeated several times, obtaining multiple first bus insulation against ground electricity Resistance R_F1With the second bus insulation against ground resistance R_F2Calculated value after, more multiple calculated values are carried out including ask arithmetic mean of instantaneous value, in Place value, sliding average, median mean value, or the end value obtaining after the data processing of other modes.

Described device also includes DC power source unit.DC power source unit can be using external power supply it is also possible to by bus Alternating voltage step-down, rectification, filtering, obtain after voltage stabilizing.

Claims (10)

1. a kind of IT electric power system insulating properties on-Line Monitor Device it is characterised in that：Take including controller unit, insulating signal Sample unit, voltage sampling unit；

Described voltage sampling unit is used for obtaining bus ac voltage signal and delivering to controller unit；

Described insulating signal sampling unit is used for obtaining the insulation against ground signal of IT electric power system and delivering to controller unit.

2. IT electric power system insulating properties on-Line Monitor Device according to claim 1 it is characterised in that：Described insulation letter Number sampling unit includes the first sample of signal branch road, secondary signal sampling slip and sample resistance；First sample of signal branch road Including the first electronic switch being connected in series, the first current-limiting resistance, secondary signal sampling slip includes the second electricity being connected in series Son switch, the second current-limiting resistance；One end of first sample of signal branch road connects to the first bus of IT electric power system, secondary signal One end of sampling slip connects to the second bus of IT electric power system；The other end of the first sample of signal branch road, secondary signal The other end of sampling slip is connected with one end of sample resistance, and the other end of sample resistance connects to protecting field.

3. IT electric power system insulating properties on-Line Monitor Device according to claim 2 it is characterised in that：Described IT powers The insulation against ground signal of system is the first bus burst pulse voltage, the second bus burst pulse voltage over the ground over the ground, by controller list Unit controls the first electronic switch, the second electronic switch pulsed to open acquisition respectively.

4. IT electric power system insulating properties on-Line Monitor Device according to claim 3 it is characterised in that：Described first electricity Son switch, the second electronic switch respectively in the peak value release of section of the positive and negative half-wave of bus alternating voltage, or respectively in mother The peak value release of section of the negative, positive half-wave of line alternating voltage.

5. IT electric power system insulating properties on-Line Monitor Device according to claim 4 it is characterised in that：Described first letter Number sampling slip also includes the first diode connected, and described secondary signal sampling slip also includes the second diode connected； First diode makes the first electronic switch open-minded in bus alternating voltage a half-wave, and the second diode makes the second electronics Switch can only be open-minded in the another one half-wave of bus alternating voltage.

6. IT electric power system insulating properties on-Line Monitor Device according to claim 5 it is characterised in that：Described first letter Number sampling slip also includes the 3rd diode, and described secondary signal sampling slip also includes the 4th diode；Described three or two pole Pipe is connected in reverse parallel on the first electronic switch, and the 4th diode reverse is connected in parallel on the second electronic switch.

7. IT electric power system insulating properties on-Line Monitor Device according to claim 3 it is characterised in that：Described first electricity Son switchs, the second electronic switch is respectively in the peak value release of section of the different positive half-waves of bus alternating voltage, or exists respectively The difference of bus alternating voltage bears the peak value release of section of half-wave.

8. the IT electric power system insulating properties on-Line Monitor Device according to any one of claim 4-7, its feature exists In：First bus insulation against ground resistance R_F1, the second bus insulation against ground resistance R_F2According to formula

$\left\{\begin{array}{c}{R}_{F1}=\frac{U_m-U_1-U_2}{U_2}\·(R_E+R_S)\\ R_{F2}=\frac{U_m-U_1-U_2}{U_1}\·(R_E+R_S)\end{array}\right.$

Calculated, wherein, R_EResistance value for the first current-limiting resistance and the second current-limiting resistance；R_SResistance value for sample resistance； U_mPeak value for bus alternating voltage；U₁First bus burst pulse voltage over the ground, U when opening for the first electronic switch₂For the second electricity Second bus burst pulse voltage over the ground when son is opened.

9. IT electric power system insulating properties on-Line Monitor Device according to claim 8 it is characterised in that：Described U₁、U₂Press Illuminated

$\left\{\begin{array}{c}{U}_1=\frac{R_E+R_S}{R_S}\·U_{C1}\\ U_2=\frac{R_E+R_S}{R_S}\·U_{C2}\end{array}\right.$

Calculated, wherein, U_C1Sample resistance R when opening for the first electronic switch_SOn voltage, U_C2Open for the second electronic switch Sample resistance R when logical_SOn voltage.

10. IT electric power system insulating properties on-Line Monitor Device according to claim 8 it is characterised in that：Controller list The concrete steps that unit realizes insulating properties on-line monitoring include：

Step one, sampling obtain the first bus burst pulse voltage, the second bus burst pulse voltage and bus alternating current over the ground over the ground Pressure data；

Step 2, calculating the first bus insulation against ground resistance and the second bus insulation against ground resistance；

Step 3, result treatment；

Step 4, return to step one.