CN112379195B - Secondary circuit detection method for bus protection - Google Patents
Secondary circuit detection method for bus protection Download PDFInfo
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- CN112379195B CN112379195B CN202011178852.1A CN202011178852A CN112379195B CN 112379195 B CN112379195 B CN 112379195B CN 202011178852 A CN202011178852 A CN 202011178852A CN 112379195 B CN112379195 B CN 112379195B
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- 238000001514 detection method Methods 0.000 title claims abstract description 15
- 230000002159 abnormal effect Effects 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims description 6
- 238000005070 sampling Methods 0.000 claims description 5
- 238000012423 maintenance Methods 0.000 abstract description 7
- 238000012512 characterization method Methods 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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Abstract
The invention discloses a secondary circuit detection method for bus protection, which comprises the following steps: s1: the controller collects switching value and analog quantity signals of all branches of the secondary circuit protected by the bus, and calculates large difference current and small difference current of each section of bus; s2: judging whether the large difference current is larger than the current threshold of the difference current, if so, executing the step S3, otherwise, executing the step S4; s3: calculating the acquired analog quantity signals of each branch, comparing the analog quantity signals with the actual value, and positioning the abnormal branch; s4: judging whether the small difference current is larger than the current threshold of the difference current, if so, executing the step S5, otherwise, executing the step S6, wherein the secondary circuit is normal; s5: adjusting the connection relation between the branch circuit and the bus, calculating the adjusted small difference current, and positioning the abnormal branch circuit; s6: the secondary circuit normal/abnormal condition is displayed. The invention detects whether the secondary circuit is abnormal in real time on line, and rapidly locates the abnormal branch, thereby improving the operation and maintenance efficiency and the operation reliability of bus protection.
Description
Technical Field
The invention relates to the field of power systems, in particular to a secondary circuit detection method for bus protection.
Background
Bus bars are very important electrical elements in an electric power system, and are important nodes for collecting and distributing system power. Often, the bus is connected with numerous electrical intervals, and the secondary circuit is complex. Bus faults caused by secondary circuit abnormality often occur, and the bus faults cause great influences such as power failure of a transformer substation, so that bus protection devices are configured for important transformer substation buses in engineering application.
The bus protection device is key relay protection equipment for protecting a bus of the transformer substation, and operation maintenance personnel are required to complete testing on the opening and closing of the bus protection device, analog sampling and the like before the bus is put into operation so as to ensure that a secondary circuit is correct. After the bus is put into operation, operation and maintenance personnel are also required to regularly overhaul the bus secondary circuit. However, the current bus secondary circuit is still mainly overhauled manually and periodically, and online intelligent detection is not realized. The operation and maintenance of the bus protection device are complicated, and the maintenance period is relatively long.
Disclosure of Invention
The invention aims to: the invention aims to solve the defects in the prior art, provides a bus protection secondary circuit detection method, and solves the problem of low operation and maintenance working efficiency of a secondary circuit.
The technical scheme is as follows: the invention discloses a bus protection secondary circuit detection method, which comprises the following steps:
s1: the controller collects switching value and analog quantity signals of all branches of the secondary circuit protected by the bus, and calculates large difference current protected by the bus and small difference current of buses of each section;
s2: the controller judges whether the large difference current is larger than the current threshold of the difference current, if yes, the step S3 is executed, otherwise, the step S4 is executed;
s3: the controller calculates the analog quantity signals of all the acquired branches, compares the analog quantity signals with the actual value and positions the abnormal branch of the secondary circuit;
s4: the controller judges whether the small difference current is larger than the current threshold of the difference current, if yes, the step S5 is executed, otherwise, the secondary circuit is normal, and the step S6 is executed;
s5: the controller adjusts the connection relation between the branch and the bus, calculates the adjusted small difference current and positions the abnormal branch of the secondary circuit;
s6: the controller outputs the secondary loop normal/abnormal condition.
The switching value comprises the connection relation between a branch and a bus, and the analog quantity signal comprises the sampling electric quantity required by realizing the bus protection function; the sampled electrical quantities include, but are not limited to, three-phase current and its sequence components, active power, and reactive power.
The step S5 includes:
s5.1: if only one section of bus has small difference current larger than the difference current flowing threshold, traversing a branch electrically connected with the section of bus, and adjusting the connection relation between the branch and the bus;
s5.2: if the small difference current of each section of bus is larger than the current threshold of the difference current, traversing all the branches, and adjusting the connection relation between each branch and the bus;
s5.3: in steps S5.1 and S5.2, after all the branches are traversed, if no abnormal branch of the secondary circuit is located, the branches are abnormal.
The method for adjusting the connection relation between the branch and the bus in S5.1 is to take the inverse, and adjust to 0 if the current value is 1, and adjust to 1 if the current value is 0.
And in the step S5.2, the connection relation between each branch and the bus is adjusted.
In step S5, the method for locating the abnormal branch of the secondary circuit is that after the connection relation is adjusted, the small difference current of the bus is smaller than the current threshold of the difference current, and the current branch is the abnormal branch.
In step S6, if the secondary circuit branches are all normal, displaying that the secondary circuit branches are normal; if an abnormal branch is positioned, outputting the number of the abnormal branch and the connection relation between the branch and a bus after adjustment, and alarming; if no abnormal branch is positioned, the connection relation between all branches and the bus and the electrical quantity information are displayed.
The differential flow has a flow threshold set according to the load condition and unbalance differential flow of the bus protection.
The beneficial effects are that: compared with the prior art, the invention has the remarkable advantages of being capable of detecting whether the secondary circuit is abnormal in real time on line, rapidly positioning the abnormal branch, and improving the operation and maintenance efficiency and the operation reliability of bus protection.
Drawings
FIG. 1 is a flow chart of a method implementation of the present invention;
fig. 2 is a schematic structural view of the dual busbar system of the present invention.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings.
The specific embodiments of the present invention will be described by taking a typical double bus wire as an example. For convenience of description, a typical dual Bus system shown in fig. 2 is defined, where two Bus sections are Bus1 and Bus2, respectively, and the system includes a Bus branch 1 and branches 2 to 20.
Calculating large difference current CZ in real time in bus protection operation: cz= Σi k ，I k K=2 to 20 for the current sample value of branch k.
Bus1 small difference current Disz1: disz1= ΣL k1 ·I k ，I k For the current sample value L of branch k connected to Bus1 k1 Characterization of whether Branch K is connected with Bus1, L when connected to Bus1 k1 The value is 1, otherwise the value is 0, k=1 to 20.
Bus2 small difference current Disz2: disz2= ΣL k2 ·I k ，I k For the current sample value L of branch k connected to Bus2 k2 Characterization of whether Branch K is connected with Bus2, L when connected to Bus2 k2 The value is 1, otherwise the value is 0, k=1 to 20.
The differential flow has a flow threshold high_threshold, which is set by comprehensively considering the load level, unbalanced differential flow and the like of the bus system, and is larger than the unbalanced differential flow when the system normally operates. And when the bus differential flow is larger than the differential flow threshold, starting secondary circuit detection.
As can be seen from fig. 1, the embodiment of the present invention comprises the following steps:
when the large difference current CZ is higher than the difference current threshold high_threshold, the sampling electric quantity of each branch is calculated, wherein the sampling electric quantity comprises, but is not limited to, three-phase current and sequence components thereof, active power, reactive power and the like. And comparing the sampled electric quantity with the actual electric quantity of the primary system, and locating an abnormal branch of the secondary circuit.
When the large difference current CZ is lower than the difference current flowing threshold high_threshold, calculating the small difference current of each Bus, and judging whether the small difference current Disz1 of the Bus1 and the small difference current Disz2 of the Bus2 are higher than the difference current flowing threshold high_threshold.
If Disz1 is higher than the differential stream flow threshold high_threshold and Disz2 is smaller than the differential stream flow threshold high_threshold, adjusting the connection relation L between the kth branch and the Bus1 k1 If the current value is 1, then adjusting to 0; and if the current value is 0, adjusting to be 1.L (L) k1 After adjustment, recalculating Disz1, and if the recalculated Disz1 is lower than a difference stream threshold high_threshold, indicating that the secondary loop of the branch K is an abnormal branch; if the Disz1 obtained by recalculation is higher than the difference stream threshold high_threshold after traversing all the branches, the secondary circuits of the branches are indicated to be abnormal;
if Disz2 is higher than the differential flow threshold high_threshold, and Disz1 is smaller than the differential flow threshold high_threshold, adjusting the connection relation L between the kth branch and the Bus2 k2 If the current value is 1, then adjusting to 0; and if the current value is 0, adjusting to be 1.L (L) k2 After adjustment, recalculating Disz2, and if the recalculated Disz2 is lower than a difference stream threshold high_threshold, indicating that the secondary loop of the branch K is an abnormal branch; if the Disz2 obtained by recalculation is higher than the difference stream threshold high_threshold after traversing all the branches, the secondary circuits of the branches are indicated to be abnormal;
if Disz1 and Dis2 are both higher than the difference stream threshold high_threshold, the connection relation between the kth branch and Bus1 is defined by L k1 Adjusted to L k2 The connection relation with Bus2 is L k2 Adjusted to L k1 When the small difference currents Disz1 and Disz2 after the adjustment of k branches are lower than the difference current threshold high_threshold, the secondary circuit of the k branches is abnormal, and the serial numbers of the abnormal branches and the connection relation between the branches and the bus after the adjustment are output; if the Disz1 or Disz2 obtained by recalculation is still higher than the difference stream threshold high_threshold after traversing all the branches, the secondary circuits of the branches are described as abnormal, and the connection relation between all the branches and the bus is output;
if Disz1 and Dis2 are both lower than the differential flow threshold high_threshold, the bus secondary circuit is characterized as not abnormal.
The controller outputs and displays the conditions of each branch in real time, and if the secondary circuits are normal, the display is normal; if the secondary circuit is abnormal, displaying the serial number of the abnormal branch of the secondary circuit and giving an alarm; if no abnormal branch of the secondary circuit is positioned, the connection relation between all the branches and the bus and the electrical quantity information are displayed, and the user is prompted to overhaul.
Claims (7)
1. The secondary circuit detection method for bus protection is characterized by comprising the following steps of:
s1: the controller collects switching value and analog quantity signals of all branches of the secondary circuit protected by the bus, and calculates large difference current protected by the bus and small difference current of buses of each section;
s2: the controller judges whether the large difference current is larger than the current threshold of the difference current, if yes, the step S3 is executed, otherwise, the step S4 is executed;
s3: the controller calculates the analog quantity signals of all the acquired branches, compares the analog quantity signals with the actual value and positions the abnormal branch of the secondary circuit;
s4: the controller judges whether the small difference current is larger than the current threshold of the difference current, if yes, the step S5 is executed, otherwise, the secondary circuit is normal, and the step S6 is executed;
s5: the controller adjusts the connection relation between the branch and the bus, calculates the adjusted small difference current and positions the abnormal branch of the secondary circuit; the method comprises the following specific steps:
s5.1: if only one section of bus has small difference current larger than the difference current flowing threshold, traversing a branch electrically connected with the section of bus, and adjusting the connection relation between the branch and the bus;
s5.2: if the small difference current of each section of bus is larger than the current threshold of the difference current, traversing all the branches, and adjusting the connection relation between each branch and the bus;
s5.3: in the steps S5.1 and S5.2, after traversing all the branches, if no abnormal branch of the secondary circuit is positioned, a plurality of branches are abnormal;
s6: the controller outputs the secondary loop normal/abnormal condition.
2. The bus bar protected secondary circuit detection method according to claim 1, wherein: the switching value comprises the connection relation between a branch and a bus, and the analog quantity signal comprises the sampling electric quantity required by realizing the bus protection function; the sampled electrical quantities include, but are not limited to, three-phase current and its sequence components, active power, and reactive power.
3. The bus bar protected secondary circuit detection method according to claim 1, wherein: in step S5.1, the method for adjusting the connection relationship between the branch and the bus is a reversal, and the current value is adjusted to 0 if it is 1, and to 1 if it is 0.
4. The bus bar protected secondary circuit detection method according to claim 1, wherein: and in the step S5.2, the connection relation between each branch and the bus is adjusted.
5. The bus bar protected secondary circuit detection method according to claim 1, wherein: in step S5, the method for locating the abnormal branch of the secondary circuit is that after the connection relation is adjusted, the small difference current of the bus is smaller than the current threshold of the difference current, and the current branch is the abnormal branch.
6. The bus bar protected secondary circuit detection method according to claim 1, wherein: in step S6, if the secondary circuit branches are all normal, displaying that the secondary circuit branches are normal; if an abnormal branch is positioned, outputting the number of the abnormal branch and the connection relation between the branch and a bus after adjustment, and alarming; if no abnormal branch is positioned, the connection relation between all branches and the bus and the electrical quantity information are displayed.
7. The bus bar protected secondary circuit detection method according to claim 1, wherein: the differential flow has a flow threshold set according to the load condition and unbalance differential flow of the bus protection.
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| CN202011178852.1A CN112379195B (en) | 2020-10-29 | 2020-10-29 | Secondary circuit detection method for bus protection |
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| CN202011178852.1A CN112379195B (en) | 2020-10-29 | 2020-10-29 | Secondary circuit detection method for bus protection |
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| CN112379195B true CN112379195B (en) | 2023-04-25 |
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| CN102879671A (en) * | 2012-09-17 | 2013-01-16 | 华北电力大学 | Method for judging inrush current locking of equivalent instantaneous inductance for protection of extra-high voltage regulating transformer |
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| CN110646692A (en) * | 2019-09-16 | 2020-01-03 | 积成电子股份有限公司 | On-site bus protection automatic on-load test method and test module |
| CN111007439A (en) * | 2019-12-24 | 2020-04-14 | 深圳供电局有限公司 | Transformer substation bus protection secondary circuit commissioning on-load test method |
| CN111426983A (en) * | 2020-05-20 | 2020-07-17 | 国网河南省电力公司商丘供电公司 | Single-phase earth fault positioning system of power distribution overhead cable hybrid line |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7034554B2 (en) * | 2003-08-19 | 2006-04-25 | Eaton Corporation | Method and apparatus for measuring impedance across pressure joints in a power distribution system |
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- 2020-10-29 CN CN202011178852.1A patent/CN112379195B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102879671A (en) * | 2012-09-17 | 2013-01-16 | 华北电力大学 | Method for judging inrush current locking of equivalent instantaneous inductance for protection of extra-high voltage regulating transformer |
| CN105044530A (en) * | 2015-08-13 | 2015-11-11 | 国家电网公司 | DM5000E-based smart substation busbar protection test method |
| CN110646692A (en) * | 2019-09-16 | 2020-01-03 | 积成电子股份有限公司 | On-site bus protection automatic on-load test method and test module |
| CN111007439A (en) * | 2019-12-24 | 2020-04-14 | 深圳供电局有限公司 | Transformer substation bus protection secondary circuit commissioning on-load test method |
| CN111426983A (en) * | 2020-05-20 | 2020-07-17 | 国网河南省电力公司商丘供电公司 | Single-phase earth fault positioning system of power distribution overhead cable hybrid line |
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