CN108508400A - Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument - Google Patents
Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument Download PDFInfo
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- CN108508400A CN108508400A CN201810294636.XA CN201810294636A CN108508400A CN 108508400 A CN108508400 A CN 108508400A CN 201810294636 A CN201810294636 A CN 201810294636A CN 108508400 A CN108508400 A CN 108508400A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument, the busbar positive and negative polarities of DC system insulating monitoring instrument are accessed to the resistance of different resistance values over the ground respectively, busbar positive and negative anodes voltage-to-ground is different because of the resistance value difference that both sides are accessed.
Description
Technical field
The present invention relates to electricity fields, and in particular to direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument
Review one's lessons by oneself correction method.
Background technology
The direct current system online insulated monitor detection branch common method that insulate is 2 kinds, i.e., alternating current signal detection method and
DC leakage current detection method.DC leakage current detection method has detection speed fast, the features such as influence by branch distribution capacity,
Through more and more universal.The core element used in this method is Hall sensor.Common hall sensing in branch insulation detection
Tolerance journey is generally several to tens millivolts, and principle is to export corresponding voltage according to the electric current of flows through sensor centre bore, electricity
Stream has forward and reverse, the voltage of output also to divide positive voltage and negative voltage.When no current flows through in Hall sensor, sensor
Output voltage values be zero.
Hall sensor has the characteristics that precision is high, the linearity is good, but there is also defects.Most apparent is exactly mutual inductor
In the long-term use, by temperature, humidity, electric current crosses range, the influence of the factors such as aging, and zero can drift about.
After zero is drifted about, branch insulation calculated value will become inaccurate.This routine side is solved the problems, such as at this stage
Method is manual calibration, and the entire DC power system such as needs is in maintenance down state, there is a problem of calibration cycle length,
To system normal operation, there are hidden danger for the presence of drift.
Invention content
In order to solve the above technical problem, the present invention provides direct current instrument transformer zeros in a kind of DC system insulating monitoring instrument
Correction method is reviewed one's lessons by oneself in drift.
Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument, and straight-flow system is insulated and is supervised
The busbar positive and negative polarities for surveying instrument access the resistance of different resistance values, the electricity that busbar positive and negative anodes voltage-to-ground is accessed by both sides over the ground respectively
Resistance value is different and different, and the calculation formula of branch detection insulation is as follows：
I1=U1/R1, I2=U2/R2, I3=U3/R1, I4=U4/R2, U1, U2 and U3, two groups of voltages of U4 are it is known that by leading
Machine is controlled and is measured by uneven bridge,
I1+I2 and two class values of I3+I4 are measured by branch leakage current sensor, respectively Ia and Ib；
Hall current sensor output valve is voltage value, so the formula that insulating monitor calculates branch current is:
I=(U-O) * K, wherein U are output voltage, and O is sensor zero point, and K is Current Voltage conversion coefficient；
From formula as can be seen that when R1 and R2 is infinitely great, Ia and Ib are all close to 0, at this point, Ua=Ub=O, passes
Output voltage is equal to zero-point voltage to sensor twice；
When host changes voltage by uneven bridge, if sensor output does not change, illustrate that R1 and R2 are very big,
Branch insulation is good, at this point, sensor output voltage may be updated as sensor zero point；If sensor output changes
The bright branch, which has insulation, to be reduced, then without update, is updated again after insulation fault exclusion.
Advantageous effect：This method can by leakage current sensor calibration cycle from 1 year or several years it is primary shorten to it is secondary more than a day
Or once a few days, and situation can be changed with dynamic monitoring drift value.
Description of the drawings
Attached drawing 1 is the circuit diagram of embodiment.
Specific implementation mode
1 invention is further explained with embodiment below in conjunction with the accompanying drawings.
Pass through imbalance comprising one group of balance bridge and one group of imbalance bridge, monitor host in DC system insulating monitoring instrument
Bridge can accurately calculate positive and negative busbar insulation against ground value.It is that busbar positive and negative polarities access identical resistance over the ground respectively to balance bridge method
The resistance of value, if DC power system insulation is good, the voltage value of positive and negative polarities over the ground is equal.
Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument, and straight-flow system is insulated and is supervised
The busbar positive and negative polarities for surveying instrument access the resistance of different resistance values, the electricity that busbar positive and negative anodes voltage-to-ground is accessed by both sides over the ground respectively
Resistance value is different and different, and the calculation formula of branch detection insulation is as follows：
I1=U1/R1, I2=U2/R2, I3=U3/R1, I4=U4/R2, U1, U2 and U3, two groups of voltages of U4 are it is known that by leading
Machine is controlled and is measured by uneven bridge；
I1+I2 and two class values of I3+I4 are measured by branch leakage current sensor, respectively Ia and Ib；
Hall current sensor output valve is voltage value, so the formula that insulating monitor calculates branch current is：
I=(U-O) * K, wherein U are output voltage, and O is sensor zero point, and K is Current Voltage conversion coefficient,
From formula as can be seen that when R1 and R2 is infinitely great, Ia and Ib are all close to 0, at this point, Ua=Ub=O, passes
Output voltage is equal to zero-point voltage to sensor twice；
When host changes voltage by uneven bridge, if sensor output does not change, illustrate that R1 and R2 are very big,
Branch insulation is good, at this point, sensor output voltage may be updated as sensor zero point；If sensor output changes
The bright branch, which has insulation, to be reduced, then without update, is updated again after insulation fault exclusion.
Obviously, the above embodiment of the present invention is intended to be merely illustrative of the present example, and not to the present invention
Embodiment restriction.For those of ordinary skill in the art, it can also make on the basis of the above description
Other various forms of variations or variation.There is no need and unable to give poor example to all embodiments.And these belong to this
The connotation changes and variations that derived from of invention still fall within protection scope of the present invention.
Claims (1)
1. correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument, it is characterised in that：By direct current
The busbar positive and negative polarities of system insulation monitor access the resistance of different resistance values over the ground respectively, and busbar positive and negative anodes voltage-to-ground is because of two
The resistance value of side access is different and different, and the calculation formula of branch detection insulation is as follows：
I1=U1/R1, I2=U2/R2, I3=U3/R1, I4=U4/R2, U1, U2 and U3, two groups of voltages of U4 by host it is known that led to
It crosses uneven bridge control and measures,
I1+I2 and two class values of I3+I4 are measured by branch leakage current sensor, respectively Ia and Ib；
Hall current sensor output valve is voltage value, so the formula that insulating monitor calculates branch current is:
I=(U-O) * K, wherein U are output voltage, and O is sensor zero point, and K is Current Voltage conversion coefficient；
As can be seen that when R1 and R2 is infinitely great from formula, Ia and Ib are all close to 0, at this point, Ua=Ub=O, sensor
Output voltage is equal to zero-point voltage twice；
When host changes voltage by uneven bridge, if sensor output does not change, illustrate that R1 and R2 are very big, branch
Insulation is good, at this point, sensor output voltage may be updated as sensor zero point；It should if sensor output changes explanation
Branch, which has insulation, to be reduced, then without update, is updated again after insulation fault exclusion.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810294636.XA CN108508400A (en) | 2018-03-30 | 2018-03-30 | Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument |
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| CN201810294636.XA CN108508400A (en) | 2018-03-30 | 2018-03-30 | Correction method is reviewed one's lessons by oneself in direct current instrument transformer null offset in a kind of DC system insulating monitoring instrument |
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| CN108508400A true CN108508400A (en) | 2018-09-07 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110780250A (en) * | 2019-09-30 | 2020-02-11 | 国创新能源汽车能源与信息创新中心(江苏)有限公司 | Automatic calibration system and method for residual current detection |
| CN110967662A (en) * | 2019-12-24 | 2020-04-07 | 国网山东省电力公司烟台供电公司 | Calibration method of DC leakage current sensor for insulation monitoring of DC system |
| CN112666435A (en) * | 2020-12-01 | 2021-04-16 | 西安麦格米特电气有限公司 | Insulation detection design method for automobile charging system facing booster circuit |
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| CN1766659A (en) * | 2005-10-25 | 2006-05-03 | 珠海泰坦科技股份有限公司 | Zero automatic detection method of positive and negative busbar insulating detection sensor |
| CN202676898U (en) * | 2012-06-18 | 2013-01-16 | 深圳市健网科技有限公司 | Insulation detection zero drift automatic correcting device of direct current power supply system |
| CN203217024U (en) * | 2013-01-10 | 2013-09-25 | 浙江中碳科技有限公司 | Balancing double-switching circuit and insulation detection device based on same |
| CN105137363A (en) * | 2015-07-16 | 2015-12-09 | 国网上海市电力公司 | Online monitoring device used for transformer station DC power supply system |
| CN105182148B (en) * | 2015-07-16 | 2017-11-24 | 国网上海市电力公司 | A kind of transforming plant DC power-supply system |
-
2018
- 2018-03-30 CN CN201810294636.XA patent/CN108508400A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1766659A (en) * | 2005-10-25 | 2006-05-03 | 珠海泰坦科技股份有限公司 | Zero automatic detection method of positive and negative busbar insulating detection sensor |
| CN202676898U (en) * | 2012-06-18 | 2013-01-16 | 深圳市健网科技有限公司 | Insulation detection zero drift automatic correcting device of direct current power supply system |
| CN203217024U (en) * | 2013-01-10 | 2013-09-25 | 浙江中碳科技有限公司 | Balancing double-switching circuit and insulation detection device based on same |
| CN105137363A (en) * | 2015-07-16 | 2015-12-09 | 国网上海市电力公司 | Online monitoring device used for transformer station DC power supply system |
| CN105182148B (en) * | 2015-07-16 | 2017-11-24 | 国网上海市电力公司 | A kind of transforming plant DC power-supply system |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110780250A (en) * | 2019-09-30 | 2020-02-11 | 国创新能源汽车能源与信息创新中心(江苏)有限公司 | Automatic calibration system and method for residual current detection |
| CN110780250B (en) * | 2019-09-30 | 2021-11-09 | 国创移动能源创新中心(江苏)有限公司 | Automatic calibration system and method for residual current detection |
| CN110967662A (en) * | 2019-12-24 | 2020-04-07 | 国网山东省电力公司烟台供电公司 | Calibration method of DC leakage current sensor for insulation monitoring of DC system |
| CN112666435A (en) * | 2020-12-01 | 2021-04-16 | 西安麦格米特电气有限公司 | Insulation detection design method for automobile charging system facing booster circuit |
| CN112666435B (en) * | 2020-12-01 | 2024-03-12 | 西安麦格米特电气有限公司 | Insulation detection design method of automobile charging system facing booster circuit |
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Application publication date: 20180907 |