CN103983857A - Direct current insulation monitoring circuit and method - Google Patents
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Abstract
The invention discloses a direct current insulation monitoring circuit and method. The monitoring circuit comprises a resistance switching unit, a first resistor, a first voltage measurement unit and a second voltage measurement unit. The resistance switching unit comprises three ends, wherein the first end is connected with the positive electrode of a monitored direct current system, the second end is connected with the negative electrode of the monitored direct current system, and the resistance switching unit can switch the resistance value between the first end and the third end and the resistance value between the second end and the third end. One end of the first resistor is connected with the third end of the resistance switching unit, and the other end of the first resistor is connected to the ground. The first voltage measurement unit is connected with the positive electrode end and the negative electrode end of the monitored direct current system. The second voltage measurement unit is connected with the two ends of the first resistor. According to the direct current insulation monitoring circuit and method, a low-voltage electronic switch device and a single bridge circuit are adopted in the monitoring circuit, so that cost of the circuit is reduced, service life of the circuit is prolonged, and reliability and practicability of the circuit are improved.
Description
Technical field
The present invention relates to electric and electronic technical field, specifically, relate to a kind of D.C. isolation observation circuit and method.
Background technology
The running status of the power equipment DC side such as current transformer directly has influence on the safety and reliability of electric system.Once there is insulation fault in the DC side of these power equipments, will cause protective relaying device misoperation, causes the even damage of high power device of power supply trouble.In order to prevent that this type of accident from occurring, and just need to use insulating monitoring circuit.
Insulating monitoring is mainly to detect Grounding Resistance for Direct-Current System, by the resistance detecting, judges whether straight-flow system DC ground fault occurs.The method of existing detection Grounding Resistance for Direct-Current System mainly contains balanced bridge method and two unbalanced electric bridge.
Fig. 1 shows the circuit theory diagrams of balanced bridge method.
As shown in Figure 1, balanced bridge method is the both positive and negative polarity equivalence stake resistance R by straight-flow system
z, R
fthe electric bridge that the resistance R 101 identical with two resistances, R102 form detects.
When system normal, when the insulation status of system is good, because now anodal and negative pole insulation against ground resistance R
zand R
zresistance equate, so only there is small out-of-balance current to flow through in relay 103, and be less than the working current of relay 103, so now relay is not worked, alarm free signal produces.
When system breaks down, during the negative or positive electrode ground connection of system, the electric bridge out of trim consisting of resistance R 101 and resistance R 102, is now flow through by larger out-of-balance current in relay 103.When this electric current is greater than the working current of relay 103, relay 103 work, produce alerting signal.
But for both positive and negative polarity equivalence stake resistance R
zand R
fwhen equal decline or numerical value approach, even if the both positive and negative polarity voltage of system has dropped to below alarm threshold, this relay 103 is not still worked.So this circuit cannot be realized the warning of above-mentioned situation.
Fig. 2 shows the circuit theory diagrams of two unbalanced electric bridges.
As shown in Figure 2, two unbalanced electric bridges be straight-flow system positive and negative busbar between two groups of resistance are set.Wherein first group of resistance comprises resistance R 201 and resistance R 202, second group of resistance comprises resistance R 203 and resistance R 204, wherein the resistance of the resistance of resistance R 201 and resistance R 204 is R, and the resistance of resistance R 202 and resistance R 203 is R', and the value of R and R' is unequal.In the process of switching in K switch, can be regarded as the location swap of R201 and R202.Distinguish the voltage at sampling switch K resistance R j two ends when diverse location, according to this voltage, can calculate the Rz of equivalent resistance over the ground and the Rf of positive and negative busbar.
Two unbalanced electric bridges are both positive and negative polarity stake resistance is equal decline in the situation that, also can detect by Uj1, Uj2 (voltage at Rj two ends when Uj1, Uj2 are respectively in Fig. 2 that K is allocated to the left side and the right), thereby make up the defect of bridge method.But two unbalanced electric bridges need to be used two cover circuit to switch back and forth, and the electronic devices and components that circuit installs additional are too much.
Based on above-mentioned situation, need badly and a kind ofly can monitor effectively, reliably the circuit of straight-flow system state of insulation.
Summary of the invention
For addressing the above problem, the invention provides a kind of D.C. isolation observation circuit, comprising:
Resistance switch unit, it comprises at least three ends, wherein, first end is connected with the positive pole of monitored straight-flow system, the second end is connected with the negative pole of described monitored straight-flow system, and described resistance switch unit can switch the resistance between the resistance between first end and the 3rd end and the second end and the 3rd end mutually;
The first resistance, its one end is connected with the 3rd end of described resistance switch unit, and the other end is connected with ground;
The first voltage measurement unit, it is connected to the positive and negative end of described monitored straight-flow system;
Second voltage measuring unit, it is connected to described the first resistance two ends.
According to one embodiment of present invention, described second voltage measuring unit changes between the second end and the 3rd end that is connected to described resistance switch unit, for measuring the voltage between described the second end and the 3rd end.
According to one embodiment of present invention, described resistance switch unit comprises:
Be connected on first end and the second resistance between the 3rd end and the 3rd resistance of described resistance switch unit;
Be connected on the second end and the 4th resistance between the 3rd end and the 5th resistance of told resistance switch unit, wherein said the 4th resistance equates with the resistance of described the 3rd resistance, and described the 5th resistance equates with the resistance of described the second resistance;
First change-over switch in parallel with described the 3rd resistance;
Second change-over switch in parallel with described the 4th resistance.
According to one embodiment of present invention, described the first change-over switch changes in parallel with described the second resistance, and described the second change-over switch changes in parallel with described the 5th resistance.
According to one embodiment of present invention, described the first change-over switch and described the second change-over switch comprise electronic relay.
According to one embodiment of present invention, described the first voltage measurement unit and second voltage measuring unit comprise voltage transformer (VT).
The present invention also provides a kind of D.C. isolation monitoring method based on D.C. isolation observation circuit as above, said method comprising the steps of:
By the first voltage measurement unit and second voltage measuring unit, obtain respectively the first voltage and second voltage;
At resistance switch unit, carry out, after resistance switching, by second voltage measuring unit, obtaining tertiary voltage;
According to described the first voltage, second voltage and tertiary voltage, calculate the equivalent parallel value of the positive and negative equivalent resistance over the ground of monitored straight-flow system;
Judge whether described equivalent parallel value is less than preset alarm threshold value, and according to judged result, determine the D.C. isolation state of described monitored straight-flow system.
According to one embodiment of present invention, if described equivalent parallel value is less than preset alarm threshold value, determine that the D.C. isolation of described monitored straight-flow system is abnormal, otherwise determine that the D.C. isolation of described monitored straight-flow system is normal.
According to one embodiment of present invention, if described equivalent parallel value is less than preset alarm threshold value, and continue default duration, determine that the D.C. isolation of described monitored straight-flow system is bad, otherwise determine that the D.C. isolation of described monitored straight-flow system is good.
According to one embodiment of present invention, according to following formula, calculate the equivalent parallel value of the positive and negative equivalent resistance over the ground of monitored straight-flow system:
Wherein, R
zthe equivalent resistance over the ground that represents monitored straight-flow system positive pole, R
fthe equivalent resistance over the ground that represents monitored straight-flow system negative pole, R
z|| R
fthe equivalent parallel value that represents the positive and negative equivalent resistance over the ground of monitored straight-flow system, R
1the resistance that represents the second resistance and the 5th resistance, R
2the resistance that represents the 3rd resistance and the 4th resistance, R
0the resistance that represents the first resistance, U
inrepresent the voltage between monitored straight-flow system both positive and negative polarity, i.e. the first voltage, U
a1represent second voltage, U
a2represent tertiary voltage.
The present invention, by the cycle detection to the switching of D.C. isolation observation circuit state and DC input voitage information, monitors equivalent resistance resistance over the ground in real time, thereby the state of insulation of judgement straight-flow system prevents from working the mischief because of the DC side ground connection of system.In observation circuit provided by the invention, adopt Low-voltage Electronic switching device and single bridge circuit, be conducive to serviceable life of reducing circuit cost and extending circuit, thereby improved the dependable with function of circuit.
Meanwhile, monitoring method provided by the invention utilizes software control algorithm to realize the insulating monitoring to straight-flow system, has reduced the investment of observation circuit hardware device, provides cost savings.Meanwhile, the default parallel connection of using in the method provided by the invention over the ground Protection parameters threshold value of equivalent resistance can arrange accordingly according to different application scenarios, has improved like this versatility of the present invention and reliability.
Other features and advantages of the present invention will be set forth in the following description, and, partly from instructions, become apparent, or understand by implementing the present invention.Object of the present invention and other advantages can be realized and be obtained by specifically noted structure in instructions, claims and accompanying drawing.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, will do simple introduction to needed accompanying drawing in embodiment or description of the Prior Art below:
Fig. 1 is the schematic diagram of D.C. isolation observation circuit in existing balanced bridge method;
Fig. 2 is the schematic diagram of D.C. isolation observation circuit in existing pair of unbalanced electric bridge;
Fig. 3 is the schematic diagram of D.C. isolation observation circuit according to an embodiment of the invention;
Fig. 4 is the equivalent circuit diagram of D.C. isolation observation circuit when the first state according to an embodiment of the invention;
Fig. 5 is the thevenin equivalent circuit figure of circuit shown in Fig. 4;
Fig. 6 is the equivalent circuit diagram of D.C. isolation observation circuit when the second state according to an embodiment of the invention;
Fig. 7 is the thevenin equivalent circuit figure of circuit shown in Fig. 6;
Fig. 8 is the process flow diagram of D.C. isolation monitoring method according to an embodiment of the invention.
Embodiment
Below with reference to drawings and Examples, describe embodiments of the present invention in detail, to the present invention, how application technology means solve technical matters whereby, and the implementation procedure of reaching technique effect can fully understand and implement according to this.It should be noted that, only otherwise form conflict, each embodiment in the present invention and each feature in each embodiment can mutually combine, and formed technical scheme is all within protection scope of the present invention.
In addition, in the step shown in the process flow diagram of accompanying drawing, can in the computer system such as one group of computer executable instructions, carry out, and, although there is shown logical order in flow process, but in some cases, can carry out shown or described step with the order being different from herein.
Fig. 3 shows the schematic diagram of the D.C. isolation observation circuit that the present embodiment provides.
As shown in Figure 3, the direct current observation circuit that the present embodiment provides comprises resistance switch unit 301, the first resistance R 0, the first voltage measurement unit SV1 and second voltage measuring unit SV2.Wherein, resistance switch unit 301 comprises three ends, and its first end 301a is connected with the positive pole of monitored straight-flow system, and the second end 301b is connected with the negative pole of monitored straight-flow system, the 3rd end 301c is connected with one end of the first resistance R 0, and the other end of the first resistance R 0 is connected with ground.Resistance switch unit 301 can switch the resistance between the resistance between first end 301a and the 3rd end 301c and the second end 301b and the 3rd end 301c mutually.It should be noted that, in other embodiments of the invention, according to the setting of side circuit, the port number that resistance switch unit 301 comprises can also, for other reasonable values, the invention is not restricted to this.
As can be seen from Figure 3, in the present embodiment, resistance switch unit 301 comprises: be connected on the second resistance R 7 and the 3rd resistance R 8 between first end 301a and the 3rd end 301c, be connected on the 4th resistance R 9 and the 5th resistance R 10 between the second end 301b and the 3rd end 301c, and be connected in parallel on the first change-over switch S1 at the 3rd resistance R 8 two ends and be connected in parallel on the second change-over switch S2 at the 4th resistance R 9 two ends.
In the present embodiment, the second resistance R 7 equates with the resistance of the 5th resistance R 10, is R
1; The 3rd resistance R 8 equates with the resistance of the 4th resistance R 9, is R
2.The K switch of using in existing pair of unbalanced electric bridge need to be used high voltage bearing device, and this has caused the high cost of whole circuit.Meanwhile, the K switch of using in two unbalanced electric bridges mostly is mechanical relay, because need frequent switching, so cause the life-span of mechanical relay shorter.In the present embodiment, the first change-over switch S1 and the second change-over switch S2 adopt the Low-voltage Electronic switching devices such as electronic relay, like this compared to existing direct current observation circuit, the circuit that the present embodiment provides can have longer serviceable life and more intelligent type of drive, is conducive to practicality and the accuracy of whole circuit.
When the first change-over switch S1 disconnects and the second change-over switch S2 closure, direct current observation circuit is when the first state, and first end 301a is the resistance that the second resistance R 7 is connected with the 3rd resistance R 8, i.e. R with the resistance between the 3rd end 301c
1+ R
2, the resistance between the second end 301b and the 3rd end 301c is the resistance of the 5th resistance R 10, i.e. R
1.
When resistance commutation circuit 301 is carried out resistance switching, when the first change-over switch S1 closure and the second change-over switch S2 disconnect, now direct current observation circuit is in the second state.Now, the resistance between the first end 301a of resistance commutation circuit 301 and the 3rd end 301c is the resistance of the second resistance R 7, i.e. R
1, the second end 301b is the resistance that the 4th resistance R 9 is connected with the 5th resistance R 10, i.e. R with the resistance between the 3rd end 301c
1+ R
2.
It should be noted that, in other embodiments of the invention, the first change-over switch and the second change-over switch are also to be arranged on other rational positions, and for example the first change-over switch is connected in parallel on the two ends of the second resistance, the second change-over switch is connected in parallel on the two ends of the 5th resistance, the invention is not restricted to this.
Like this, resistance commutation circuit 301 is carried out resistance switching and has just been realized resistance between first end 301a and the 3rd end 301c and the mutual switching of the resistance between the second end 301b and the 3rd end 301c.
In addition, in Fig. 3, R
zthe equivalent resistance over the ground that represents monitored straight-flow system positive pole, R
fthe equivalent resistance over the ground that represents monitored straight-flow system negative pole.
It should be noted that, in according to other embodiments of the invention, resistance quantity between resistance quantity between the first port of resistance switch unit and the 3rd port and the second port and the 3rd port can also increase according to actual needs, the invention is not restricted to this.
As shown in Figure 3, in the present embodiment, the first voltage measurement unit SV1 is connected to the positive and negative end of monitored straight-flow system, for measuring the voltage between monitored straight-flow system both positive and negative polarity, this voltage also can be regarded as the first end 301a of resistance switch unit 301 and the voltage between the second end 301b.Second voltage measuring unit SV2 is connected between the second end 301b and the 3rd end 301c of resistance switch unit 301, for measuring the voltage between the second end 301b and the 3rd end 301c.In the present embodiment, the first voltage measurement unit SV1 and second voltage measuring unit SV2 adopt voltage transformer (VT), but the invention is not restricted to this.
It should be noted that, in according to other embodiments of the invention, the first voltage measurement unit SV1 and second voltage measuring unit SV2 can also be arranged on other rational positions, for example, between the first end of resistance switch unit and the 3rd end, or the positions such as two ends of the first resistance, the invention is not restricted to this.
When the first change-over switch S1 disconnection and the second change-over switch S2 closure, circuit illustrated in fig. 3 can be equivalent to the circuit shown in Fig. 4.
As shown in Figure 4, the voltage U between the monitored straight-flow system both positive and negative polarity that now the first voltage measurement unit SV1 measures
in, this voltage is as the first low pressure.Voltage U between the resistance switch unit the second end that second voltage measuring unit SV2 measures and the 3rd end
m1, this voltage is as second voltage.The voltage U at the first resistance R 0 two ends so, now
a1can calculate according to following formula:
According to Thevenin theorem, the circuit shown in Fig. 4 can be equivalent to circuit as shown in Figure 5.Wherein, equivalent resistance R
a1and R
bcan according to following formula, calculate respectively:
R
a1＝(R
1+R
2)||R
1 (2)
R
b＝R
z||R
f (3)
Voltage U
oc1can calculate according to following formula:
Now, according to the circuit shown in Fig. 5 and in conjunction with formula (2)～(4), can calculate U
a1, that is:
When the first change-over switch S1 is closed and the second change-over switch S2 disconnects, circuit illustrated in fig. 3 can be equivalent to the circuit shown in Fig. 6.
As shown in Figure 6, the voltage U between the detected straight-flow system both positive and negative polarity that now the first voltage measurement unit SV1 measures
in, this voltage is the first voltage.Voltage U between the resistance switch unit the second end that second voltage measuring unit SV2 measures and the 3rd end
m2, this voltage is as tertiary voltage.The voltage U at the first resistance R 0 two ends so, now
a2can calculate according to following formula:
According to Thevenin theorem, the circuit shown in Fig. 6 can be equivalent to circuit as shown in Figure 7.Wherein, equivalent resistance R
a2and R
bcan according to following formula, calculate respectively:
R
a2＝R
1||(R
1+R
2) (7)
R
b＝R
z||R
f (8)
Voltage U
oc2can calculate according to following formula:
According to the circuit shown in Fig. 7 and in conjunction with formula (7)～(9), can calculate U
a2, that is:
In conjunction with formula (5) and formula (10), can calculate the equivalent parallel value R of the positive and negative equivalent resistance over the ground of monitored straight-flow system
zr
f, that is:
From formula (11), can find out, as long as declining over against the resistance of any one in ground equivalent resistance and negative equivalent resistance over the ground of monitored straight-flow system, all can cause that the two value in parallel reduces, and be reflected on the measured value of the first voltage measurement unit and second voltage measuring unit, thereby realize the insulating monitoring to straight-flow system.
Based on above-mentioned insulating monitoring circuit, the present invention also provides a kind of D.C. isolation monitoring method, and Fig. 8 shows the process flow diagram of the method in the present embodiment.
As shown in Figure 8, in the present embodiment, first in step S801, when direct current observation circuit is during in the first state, by the first voltage measurement unit and second voltage measuring unit, obtain respectively the voltage U between detected straight-flow system both positive and negative polarity
involtage U between (i.e. the first voltage) and resistance switch unit the second end and the 3rd end
m1(being second voltage).
In step S802, at resistance switch unit, carry out after resistance switching subsequently, DC System Monitoring, when the second state, obtains the now voltage U between resistance switch unit the second end and the 3rd end by second voltage measuring unit
m2(being tertiary voltage).
In step S803, according to the first voltage U of obtaining
in, second voltage U
m1with tertiary voltage U
m2, utilize formula (11) to calculate the equivalent parallel value R of the positive and negative equivalent resistance over the ground of monitored straight-flow system
z|| R
f.
In step S804, the equivalent parallel value R of the positive and negative equivalent resistance over the ground of the monitored straight-flow system that determining step S803 obtains
z|| R
fwhether be less than preset alarm threshold value.If equivalent parallel value R
z|| R
fmeet above-mentioned condition, in step S805, judge that the D.C. isolation of monitored straight-flow system is abnormal, may have DC earthing phenomenon; Otherwise the D.C. isolation of judging monitored system in step S806 is normal.
For the monitoring result that makes to obtain more reliable, according to other embodiments of the invention, at the equivalent parallel value R of positive and negative equivalent resistance over the ground of the monitored straight-flow system of judgement
z|| R
fduring with preset alarm threshold value big or small, can also judge this equivalent parallel value R
z|| R
fwhether in default duration, be less than constantly preset alarm threshold value, whether the D.C. isolation that judges monitored system with this is normal.Can effectively eliminate so the inaccurate problem of monitoring result that the noise because existing in circuit causes, thus make the result that obtains more accurately, reliable, improved the practicality of whole circuit.
From foregoing description, can find out, the present invention is by the cycle detection to the switching of D.C. isolation observation circuit state and DC input voitage information, monitor in real time equivalent resistance resistance over the ground, thereby the state of insulation of judgement straight-flow system prevents from working the mischief because of the DC side ground connection of system.In observation circuit provided by the invention, adopt Low-voltage Electronic switching device and single bridge circuit, be conducive to serviceable life of reducing circuit cost and extending circuit, thereby improved the dependable with function of circuit.
Meanwhile, monitoring method provided by the invention utilizes software control algorithm to realize the insulating monitoring to straight-flow system, has reduced the investment of observation circuit hardware device, provides cost savings.Meanwhile, the default parallel connection of using in the method provided by the invention over the ground Protection parameters threshold value of equivalent resistance can arrange accordingly according to different application scenarios, has improved like this versatility of the present invention and reliability.
Although the disclosed embodiment of the present invention as above, the embodiment that described content just adopts for the ease of understanding the present invention, not in order to limit the present invention.Technician in any the technical field of the invention; do not departing under the prerequisite of the disclosed spirit and scope of the present invention; can do any modification and variation what implement in form and in details; but scope of patent protection of the present invention, still must be as the criterion with the scope that appending claims was defined.
Claims (10)
1. a D.C. isolation observation circuit, is characterized in that, comprising:
Resistance switch unit, it comprises at least three ends, wherein, first end is connected with the positive pole of monitored straight-flow system, the second end is connected with the negative pole of described monitored straight-flow system, and described resistance switch unit can switch the resistance between the resistance between first end and the 3rd end and the second end and the 3rd end mutually;
The first resistance, its one end is connected with the 3rd end of described resistance switch unit, and the other end is connected with ground;
The first voltage measurement unit, it is connected to the positive and negative end of described monitored straight-flow system;
Second voltage measuring unit, it is connected to described the first resistance two ends.
2. circuit as claimed in claim 1, is characterized in that, described second voltage measuring unit changes between the second end and the 3rd end that is connected to described resistance switch unit, for measuring the voltage between described the second end and the 3rd end.
3. circuit as claimed in claim 1 or 2, is characterized in that, described resistance switch unit comprises:
Be connected on first end and the second resistance between the 3rd end and the 3rd resistance of described resistance switch unit;
Be connected on the second end and the 4th resistance between the 3rd end and the 5th resistance of told resistance switch unit, wherein said the 4th resistance equates with the resistance of described the 3rd resistance, and described the 5th resistance equates with the resistance of described the second resistance;
First change-over switch in parallel with described the 3rd resistance;
Second change-over switch in parallel with described the 4th resistance.
4. circuit as claimed in claim 3, is characterized in that,
Described the first change-over switch changes in parallel with described the second resistance, and described the second change-over switch changes in parallel with described the 5th resistance.
5. the circuit as described in claim 3 or 4, is characterized in that, described the first change-over switch and described the second change-over switch comprise electronic relay.
6. the circuit as described in any one in claim 1～5, is characterized in that, described the first voltage measurement unit and second voltage measuring unit comprise voltage transformer (VT).
7. a D.C. isolation monitoring method for the circuit based on as described in any one in claim 1～6, is characterized in that, comprises the following steps:
By the first voltage measurement unit and second voltage measuring unit, obtain respectively the first voltage and second voltage;
At resistance switch unit, carry out, after resistance switching, by second voltage measuring unit, obtaining tertiary voltage;
According to described the first voltage, second voltage and tertiary voltage, calculate the equivalent parallel value of the positive and negative equivalent resistance over the ground of monitored straight-flow system;
Judge whether described equivalent parallel value is less than preset alarm threshold value, and according to judged result, determine the D.C. isolation state of described monitored straight-flow system.
8. method as claimed in claim 7, is characterized in that,
If described equivalent parallel value is less than preset alarm threshold value, determines that the D.C. isolation of described monitored straight-flow system is abnormal, otherwise determine that the D.C. isolation of described monitored straight-flow system is normal.
9. method as claimed in claim 7, is characterized in that,
If described equivalent parallel value is less than preset alarm threshold value, and continue default duration, determine that the D.C. isolation of described monitored straight-flow system is bad, otherwise determine that the D.C. isolation of described monitored straight-flow system is good.
10. the method as described in any one in claim 7～9, is characterized in that, calculates the equivalent parallel value of the positive and negative equivalent resistance over the ground of monitored straight-flow system according to following formula:
Wherein, R
zthe equivalent resistance over the ground that represents monitored straight-flow system positive pole, R
fthe equivalent resistance over the ground that represents monitored straight-flow system negative pole, R
z|| R
fthe equivalent parallel value that represents the positive and negative equivalent resistance over the ground of monitored straight-flow system, R
1the resistance that represents the second resistance and the 5th resistance, R
2the resistance that represents the 3rd resistance and the 4th resistance, R
0the resistance that represents the first resistance, U
inrepresent the first voltage, i.e. voltage between monitored straight-flow system both positive and negative polarity, U
a1represent second voltage, U
a2represent tertiary voltage.
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| CN104535850A (en) * | 2014-12-09 | 2015-04-22 | 许继电气股份有限公司 | Direct-current insulation monitoring device |
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| CN108303588A (en) * | 2018-04-09 | 2018-07-20 | 骆驼集团武汉光谷研发中心有限公司 | A kind of Insulation Inspection Device for Direct-Current System based on nonequilibrium bridge |
| CN108303588B (en) * | 2018-04-09 | 2023-09-01 | 骆驼集团武汉光谷研发中心有限公司 | DC system insulation monitoring device based on unbalanced bridge |
| CN108445365B (en) * | 2018-04-26 | 2020-08-11 | 湖北三江航天万峰科技发展有限公司 | Automatic insulation impedance monitoring device |
| CN108445365A (en) * | 2018-04-26 | 2018-08-24 | 湖北三江航天万峰科技发展有限公司 | A kind of insulation impedance automated watch-keeping facility |
| RU2739386C2 (en) * | 2019-01-29 | 2020-12-23 | Федеральное государственное казенное военное образовательное учреждение высшего образования "Военный учебно-научный центр Военно-Морского Флота "Военно-морская академия им. Адмирала Флота Советского Союза Н.Г. Кузнецова" | Method for determination of insulation resistance reduction point |
| RU2736328C1 (en) * | 2019-12-12 | 2020-11-13 | Федеральное государственное казенное военное образовательное учреждение высшего образования "Военный учебно-научный центр Военно-Морского Флота "Военно-морская академия имени Адмирала флота Советского Союза Н.Г. Кузнецова" | Method for remote determination of insulation resistance reduction point in deenergised electric circuit |
| CN112986683A (en) * | 2019-12-18 | 2021-06-18 | 观致汽车有限公司 | Insulation resistance detection device |
| CN111896854A (en) * | 2020-06-28 | 2020-11-06 | 杭州中恒电气股份有限公司 | Switching circuit and direct current system insulation detection device and method |
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| US12066479B2 (en) | 2022-03-22 | 2024-08-20 | Delta Electronics, Inc. | Insulation resistance detection circuit and method of detecting insulation resistance |
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