CN112363085B - PT broken line identification method and device for intelligent substation - Google Patents
PT broken line identification method and device for intelligent substation Download PDFInfo
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Abstract
A PT broken line identification method and device of an intelligent transformer substation, the method comprises the steps of collecting busbar voltages of all sections, currents of all intervals of busbar section wiring, positions of all interval circuit breakers and positions of section circuit breakers in real time; judging whether to start the PT disconnection recognition of the voltage transformer according to preset conditions; judging whether PT wire breakage identification meets a judging condition, if so, sending PT wire breakage alarm signals in a delay mode, and locking and detecting synchronous closing and non-voltage closing. The invention adopts the multi-interval voltage and current quantity comprehensive discrimination collected by the cluster measurement and control device, identifies PT broken lines according to the characteristics of PT broken lines and system faults, can discriminate according to the voltage on another section of bus in parallel operation, additionally introduces other interval currents on the same bus to assist discrimination, locks PT broken line discrimination when the current changes, solves the problem of false report or incorrect identification of PT broken lines, and improves the reliability of PT broken line identification.
Description
Technical Field
The invention relates to the technical field of intelligent substations, in particular to a PT disconnection recognition method and device for an intelligent substation.
Background
In recent years, intelligent substations are built and gradually popularized and applied on a large scale, and compared with the traditional substations, the intelligent substations have a plurality of advantages, and are mainly characterized in that: (1) The digital signal transmission and processing are adopted, so that the application range is wide, the precision is high, the stability and the efficiency are high, and the data sharing is convenient. The optical fiber is used as a digital transmission carrier and has the advantages of large transmission capacity, low loss, long distance, strong anti-interference capability, good lightning protection performance, economy, environmental protection and the like. (2) The comprehensive IEC61850 protocol is adopted, the information and communication model is unified, the layered architecture of three layers and two networks is adopted, the digital acquisition and the networked information exchange of the transformer station information are realized, the measurement and control and the voltage class protection of 110kV and below are all in single-set configuration, the hidden danger of functional failure caused by single-point faults exists, the overall reliability is not high, the unmanned requirement of the transformer station cannot be completely met, and the safe and stable operation of the power system is seriously influenced.
In order to better adapt to the unattended operation requirement of a transformer substation, the safe and stable operation level of a power grid is improved, the operation efficiency of the power grid is improved, the construction and operation cost is reduced, and in the aspect of a transformer substation automation system, a transformer substation measurement and control device belongs to spacer layer equipment in a transformer substation secondary system and is core equipment of a spacer layer of the transformer substation automation system. The upper connection station is connected with layer control equipment, including a monitoring background, a telecontrol device and the like; the method plays a role in supporting the up-down connection of the equipment of the lower connection process layer, including an intelligent terminal, a merging unit and the like.
With the rapid development of power grids and computer technologies, data acquisition and processing capacity are continuously enhanced, system functions are greatly developed, but the reliability and timeliness requirements of all levels of main and sub station systems on various information are not fully met. At present, configuration requirements of secondary equipment in intelligent substations with different voltage levels in China are different, a voltage level substation with 110kV and below adopts a measurement and control integrated configuration, and voltage levels with 220kV and above adopt measurement and control devices which are independently configured. In general, most substations consider cost factors, and measurement and control are configured in a single set, namely, each interval is provided with only one set of measurement and control device. This brings certain hidden trouble to the safe and stable operation of transformer substation, has following problem.
(1) Single set mode operation has low reliability
In the single configuration mode, all interval measurement and control are not reserved. When the interval measurement and control fault or overhauling and exiting operation is carried out, the interval measurement and control function is lost due to the fact that standby measurement and control is not carried out, and serious threat is caused to the safety of remote centralized monitoring of the unattended transformer substation. In addition, the single-set mode has a larger defect in the aspect of data reliability, and because only single-set equipment performs information acquisition, if abnormal data or data errors occur in a certain measurement and control, the error data cannot be found because of no comparison data. Therefore, the current single-set operation mode cannot fully support the rapid development of a future power grid. There is an urgent need for expansion and innovation in information providing mechanisms.
(2) Failure detection and control
For a single set of measurement and control operation mode, if the measurement and control fails, the fault needs to be discovered quickly, and the network operation time of the fault measurement and control is shortened. However, at present, no equipment or method for rapidly finding and alarming faults is provided, and whether the equipment fails or not is judged only by a manual mode. If faults are easily found, such as network disconnection, the judging time is short, and if faults are not easily found, such as error data, the judging time is completely dependent on the technical level and experience of operators, so that the safe operation of a remote control center and a transformer substation monitoring system is seriously influenced.
As the main equipment for collecting the operation data information of the intelligent substation and executing the operation control of primary equipment, the measurement and control device is an important foundation for realizing the safe and stable operation of the system. However, in the aspect of improving the reliability of the measurement and control function of the transformer substation, the industry mainly refers to the idea of protection dualization, and discusses and researches on a double-set configuration scheme of the measurement and control device, but due to the problems of insufficient equipment standardization, overhigh double-set configuration cost, complex system operation and maintenance and the like, a scheme which can be used for engineering implementation, popularization and application is not formed all the time, and the problem of redundant standby mechanism deficiency of the transformer substation measurement and control device is not solved effectively.
At present, the intelligent substation measurement and control devices running in China are all in single-set configuration, measurement and control functions are realized at intervals, and functional redundancy is lacked. At present, the PT disconnection judgment of the measurement and control function is carried out by only adopting voltage and current quantity at single intervals, when any one of the following two conditions is met, the PT disconnection alarm is reported after 10 seconds, and if the condition is not met, the PT disconnection alarm returns:
1. any phase of the current is greater than 0.005I N At the same time, any phase of voltage is less than 0.3U N And the positive sequence voltage is less than 0.7U N ；
2. Negative sequence voltage or zero sequence voltage (self-produced) greater than 0.1U N 。
Wherein I is N For CT secondary rating (1A or 5A), U N Is PT secondary rated (57.7V).
Because the current measurement and control function PT disconnection is only judged by adopting voltage and current quantity at single interval, when the interval no-load or load current is less than 0.005I N When the PT is broken by three phases, the PT cannot be correctly identified. In addition, for a slow-climbing high-resistance ground fault, due to long fault duration, when the negative sequence voltage or the zero sequence voltage is greater than 0.1U N The PT wire break is also misreported.
Disclosure of Invention
The invention aims to provide a PT disconnection recognition method and device for an intelligent transformer substation, which are used for solving the problem that the current transformer substation spacer layer measurement and control function adopts single-interval voltage and current to judge, when the PT three-phase disconnection occurs when the interval is empty or the load current is small, the PT disconnection cannot be correctly recognized, and the PT disconnection can be misreported for a slowly-climbing high-resistance ground fault.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the invention provides a PT disconnection recognition method for an intelligent substation, which comprises the following steps of;
collecting the busbar voltage of all the sections, the current of all the intervals of busbar section wiring, the positions of all the interval circuit breakers and the positions of the section circuit breakers in real time;
judging whether to start the PT disconnection recognition of the voltage transformer according to preset conditions;
if the preset condition is met, PT disconnection identification is started; otherwise, continuing to perform the step of real-time acquisition;
if the PT disconnection identification meets the judgment condition, a PT disconnection alarm signal is sent in a delayed mode, and synchronous closing and non-voltage closing are closed; otherwise, continuing the step of real-time acquisition.
Further, the preset conditions for starting the voltage transformer PT disconnection recognition include:
U Φ1 (t-2T)-U Φ1 (t)＞0.1U N (1)
if the formula (1) is established, starting the voltage transformer PT disconnection recognition;
wherein U is Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U Φ1 (T-2T) is A, B, C phase voltage amplitude two weeks before the bus where PT is located when the disconnection is started; u (U) N Is the PT secondary rated value.
Further, the PT disconnection recognition includes sequentially judging: (1) The positive sequence voltage, the negative sequence voltage or the zero sequence voltage of the bus where the PT is located, and the positions of all the circuit breakers at intervals or whether current exists on the bus where the PT is located; (2) PT broken lines identify whether all interval currents on the bus change or not when the PT broken lines are started; (3) And judging the position of the sectionalized breaker, and judging whether the sectional bus voltage values are different when the sectionalized breaker is in a closing position.
Further, determining the positive sequence voltage, the negative sequence voltage or the zero sequence voltage of the bus where the condition (1) PT is located, and determining whether the current exists or not at all the circuit breaker positions of the interval on the bus where the PT is located, including:
judging whether any phase voltage of a bus where PT is located is low and positive sequence voltage is low and whether current or a breaker is in a closing position at any interval of the corresponding bus, or whether PT has negative sequence voltage or zero sequence voltage, wherein a judgment equation is as follows:
or (b)
U 2.1 (t)＞0.1U N (3)
Or (b)
3U 0.1 (t)＞0.1U N (4)
If one of the formulas (2), (3) or (4) is satisfied, continuing to judge the judging condition (2), otherwise, ending the judgment of PT disconnection recognition;
wherein U is Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U 1.1 (t) is positive sequence voltage amplitude of bus where PT is located when PT wire breakage identification is started, U 2.1 (t) is the negative sequence voltage amplitude of the bus where PT is located when PT wire breakage identification is started, U 0.1 (t) is the zero sequence voltage amplitude of the bus where PT is located when PT wire breakage identification is started, I Φ1 (t) A, B, C phase current amplitude corresponding to any interval of the bus at the start of PT wire breakage identification, and DL is the position of the breaker corresponding to any interval of the bus at the start of PT wire breakage identification; i N And protecting the CT secondary rated value for the corresponding bus.
Further, judging whether all interval currents on the bus are changed when the PT disconnection recognition of the condition (2) is started, and comprising the following steps:
when PT wire breakage identification is started, zero sequence current does not exist at all intervals of corresponding buses, phase current does not change, and a discrimination equation is as follows:
if the above formula (5) is satisfied, continuing to judge the judging condition (3), otherwise, ending the judgment of PT disconnection recognition;
i in the above Φ1 (t) is the A, B, C phase current amplitude of any interval corresponding to the bus when PT disconnection recognition is started, I Φ1 (T-2T) is A, B, C phase current amplitude which is two weeks before the corresponding bus interval when PT disconnection is started, I 0.1 (t) is the three-phase self-produced zero-sequence current amplitude corresponding to the bus interval during the disconnection starting, I N And protecting the CT secondary rated value for the corresponding bus.
Further, the judging condition (3) judges the position of the sectionalized breaker, judges whether the sectional bus voltage values are different when the sectionalized breaker is at the closing position, and includes:
if the sectional circuit breaker is at a closing position, the amplitudes of bus voltages at two sides of the sectional circuit breaker are the same, the other section of bus PT has no zero sequence voltage and no negative sequence voltage when PT is disconnected, the amplitudes of the two sections of bus voltages are different, and a discrimination equation is as follows:
if the above formula (6) is satisfied, sending a PT disconnection warning signal, otherwise, ending the judgment of PT disconnection recognition;
wherein U is 2.2 (t) is the negative sequence voltage amplitude of the other bus section when the disconnection is started, U 0.2 (t) is the zero sequence voltage amplitude of another bus at the time of starting the disconnection, U Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U Φ2 (t) is A, B, C phase voltage amplitude of another bus at break starting, U N For PT secondary rating
If the sectional breaker is not at the closing position, the PT wire breakage alarm signal is directly sent.
Further, the delay sending the PT disconnection warning signal includes delay 10s sending the PT disconnection warning signal.
The second aspect of the present invention provides a PT disconnection identifying device for an intelligent substation, which performs PT disconnection identifying and judging according to the PT disconnection identifying method for the intelligent substation as described above, including:
the collecting module is used for collecting the voltages of all the sectional buses, currents at all intervals of bus sectional wiring, the positions of all the interval circuit breakers and the positions of the sectional circuit breakers in real time;
the PT wire breakage identification starting judgment module judges whether to start the PT wire breakage identification of the voltage transformer according to preset conditions; if the preset condition is met, PT disconnection identification is started;
and the PT wire breakage identification judging module judges whether the PT wire breakage identification meets the judging condition, and if so, the PT wire breakage alarm signal is sent in a delayed mode, and the synchronous closing and the non-voltage closing are detected in a locking mode.
Further, the intelligent substation comprises an entity measurement and control module and a cluster measurement and control module, each virtual measurement and control unit in the cluster measurement and control module corresponds to each entity measurement and control unit in the entity measurement and control module one by one, and when the entity measurement and control unit fails, the intelligent substation is automatically switched to the corresponding virtual measurement and control unit in the cluster measurement and control module according to the interval 1 to 1.
Further, the virtual measurement and control unit uses ICD model, CID configuration, interlocking rule and operation parameter of the entity measurement and control unit; when the virtual measurement and control unit starts to operate, the communication parameters, the IP address, the multicast address and the APPID of the process layer GOOSE control block of the entity measurement and control unit are used.
In summary, the invention provides a method and a device for identifying PT broken lines of an intelligent substation, wherein the method comprises the steps of collecting bus voltages of all sections, currents of all intervals of bus section wiring, positions of all intervals of circuit breakers and positions of the section circuit breakers in real time; judging whether to start the PT disconnection recognition of the voltage transformer according to preset conditions; judging whether PT wire breakage identification meets a judging condition, if so, sending PT wire breakage alarm signals in a delay mode, and locking and detecting synchronous closing and non-voltage closing. The invention adopts the multi-interval voltage and current quantity comprehensive discrimination collected by the cluster measurement and control device, identifies PT broken lines according to the characteristics of PT broken lines and system faults, can discriminate according to the voltage on another section of bus in parallel operation, additionally introduces other interval currents on the same bus to assist discrimination, locks PT broken line discrimination when the current changes, solves the problem of false report or incorrect identification of PT broken lines, and improves the reliability of PT broken line identification.
Drawings
Fig. 1 is a flow chart of a smart substation PT disconnection recognition method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a bus structure of a smart substation according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a judging flow of a PT disconnection identifying method according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a frame of a smart substation PT disconnection recognition device according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a mode of intelligent substation measurement and control function adopting single-interval entity measurement and control+cluster measurement and control according to an embodiment of the present invention.
Detailed Description
The objects, technical solutions and advantages of the present invention will become more apparent by the following detailed description of the present invention with reference to the accompanying drawings. It should be understood that the description is only illustrative and is not intended to limit the scope of the invention. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention.
The first aspect of the invention provides a method for identifying PT disconnection of an intelligent substation, which is shown in fig. 1 and comprises the following steps of;
step S100, collecting bus voltage of all segments, current of all intervals of bus segment wiring and positions of all interval circuit breakers and positions of segment circuit breakers in real time.
PT (potential transformer Potential Transformer abbreviated as PT) is an instrument for converting voltage, similar to a transformer. As shown in fig. 2, the intelligent substation includes two-section buses I, II (taking two sections as an example, the number of buses is not limited to this), a sectionalized breaker DL1 is included between the two-section buses, voltage transformers PT1 and PT2 are respectively arranged on the buses, and breakers DL2, DL3, DL4 and DL5 are arranged on all the intervals. The cluster measurement and control device collects currents TA1, TA2, TA3, TA4 and TA5 of all intervals of single-bus segmented wiring, two-section bus voltages PT1 and PT2, and breaker positions DL1, DL2, DL3, DL4 and DL5 of all intervals, wherein DL1 is a segmented breaker, DL2 and DL3 are located in an I bus, and DL4 and DL5 are located in a II bus. And DL1 is the parallel operation of the two sections of buses when the switch is in the switch-on position.
Step S200, judging whether to start voltage transformer PT disconnection recognition according to preset conditions: if the preset condition is met, PT disconnection identification is started; otherwise, the step S100 of real-time acquisition is continued.
Specifically, the preset conditions for starting the voltage transformer PT disconnection recognition include:
U Φ1 (t-2T)-U Φ1 (t)＞0.1U N (1)
if the formula (1) is established, starting the voltage transformer PT disconnection recognition; wherein U is Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U Φ1 (T-2T) is PT at the time of wire breakage initiationA, B, C phase voltage magnitude two weeks before bus; u (U) N For PT secondary rating, preferably U N Can be 57.7V.
Step S300, if PT disconnection identification meets the judgment condition, a PT disconnection warning signal is sent in a delayed mode (preferably, the PT disconnection warning signal can be sent in a delayed mode for 10 seconds), and synchronous closing and non-voltage closing are closed; otherwise, continuing the step of real-time acquisition.
Further, the PT disconnection recognition includes sequentially judging: (1) The positive sequence voltage, the negative sequence voltage or the zero sequence voltage of the bus where the PT is located, and the positions of all the circuit breakers at intervals or whether current exists on the bus where the PT is located; (2) PT broken lines identify whether all interval currents on the bus change or not when the PT broken lines are started; (3) And judging the position of the sectionalized breaker, and judging whether the sectional bus voltage values are different when the sectionalized breaker is in a closing position. As shown in fig. 3, in the intelligent substation cluster measurement and control function PT disconnection identification method, after voltage has abrupt change, PT disconnection identification is started, when PT positive sequence voltage is low and an interval breaker is in a closing position or has current, or has negative sequence voltage or zero sequence voltage, all interval currents on a bus do not change during starting, if a sectionalized breaker DL1 is in a closing position, it is also required to identify that voltage values of two sections of buses are different, all conditions meet time delay to send PT disconnection alarm signals, and meanwhile, the synchronous closing and no-pressing-brake function is locked.
Specifically, judging the values of positive sequence voltage, negative sequence voltage or zero sequence voltage of the bus where the PT is located in condition (1), and determining whether the current exists or not at all the circuit breaker positions at intervals on the bus where the PT is located, including:
judging whether any phase voltage of a bus where PT is located is low and positive sequence voltage is low and whether current or a breaker is in a closing position at any interval of the corresponding bus, or whether PT has negative sequence voltage or zero sequence voltage, wherein a judgment equation is as follows:
or (b)
U 2.1 (t)＞0.1U N (3)
Or (b)
3U 0.1 (t)＞0.1U N (4)
If one of the formulas (2), (3) or (4) is satisfied, continuing to judge the judging condition (2), otherwise, ending the judgment of PT disconnection recognition; wherein U is Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U 1.1 (t) is positive sequence voltage amplitude of bus where PT is located when PT wire breakage identification is started, U 2.1 (t) is the negative sequence voltage amplitude of the bus where PT is located when PT wire breakage identification is started, U 0.1 (t) is the zero sequence voltage amplitude of the bus where PT is located when PT wire breakage identification is started, I Φ1 (t) A, B, C phase current amplitude corresponding to any interval of the bus at the start of PT wire breakage identification, and DL is the position of the breaker corresponding to any interval of the bus at the start of PT wire breakage identification; i N CT secondary ratings (specifically, 1A or 5A may be selected) are protected for the corresponding bus bars. The interval currents corresponding to the I-section bus PT1 are TA1, TA2 and TA3, and the interval breakers corresponding to the I-section bus PT1 are DL1, DL2 and DL3; the interval currents corresponding to the II-stage bus PT2 are TA1, TA4 and TA5, and the interval breakers corresponding to the II-stage bus PT2 are DL1, DL4 and DL5.
Specifically, judging whether all interval currents on the bus change or not when the PT disconnection identification is started under the condition (2) comprises the following steps:
when PT wire breakage identification is started, zero sequence current does not exist at all intervals of corresponding buses, phase current does not change, and a discrimination equation is as follows:
if the above formula (5) is satisfied, continuing to judge the judging condition (3), otherwise, ending the judgment of PT disconnection recognition; i in the above Φ1 (t) is the A, B, C phase current amplitude of any interval corresponding to the bus when PT disconnection recognition is started, I Φ1 (T-2T) is A, B, C phase current amplitude which is two weeks before the corresponding bus interval when PT disconnection is started, I 0.1 (t) is the three-phase self-produced zero-sequence current amplitude corresponding to the bus interval during the disconnection starting, I N And protecting the CT secondary rated value for the corresponding bus.
Specifically, the judging condition (3) judges the position of the sectionalized breaker, judges whether the sectional bus voltage values are different when the sectionalized breaker is at the closing position, and includes:
if the sectional circuit breaker is at a closing position, the amplitudes of bus voltages at two sides of the sectional circuit breaker are the same, the other section of bus PT has no zero sequence voltage and no negative sequence voltage when PT is disconnected, the amplitudes of the two sections of bus voltages are different, and a discrimination equation is as follows:
if the above formula (6) is satisfied, sending a PT disconnection warning signal, otherwise, ending the judgment of PT disconnection recognition; wherein U is 2.2 (t) is the negative sequence voltage amplitude of the other bus section when the disconnection is started, U 0.2 (t) is the zero sequence voltage amplitude of another bus at the time of starting the disconnection, U Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U Φ2 (t) is A, B, C phase voltage amplitude of another bus at break starting, U N The PT secondary rated value;
if the sectional breaker is not at the closing position, the PT wire breakage alarm signal is directly sent.
Further, the delay sending the PT disconnection warning signal includes delay 10s sending the PT disconnection warning signal.
The second aspect of the present invention provides a PT disconnection identifying device for a smart substation, which performs PT disconnection identifying and determining according to the PT disconnection identifying method for a smart substation as described above, as shown in fig. 4, including: the collecting module is used for collecting the voltages of all the sectional buses, currents at all intervals of bus sectional wiring, the positions of all the interval circuit breakers and the positions of the sectional circuit breakers in real time; the PT wire breakage identification starting judgment module judges whether to start the PT wire breakage identification of the voltage transformer according to preset conditions; if the preset condition is met, PT disconnection identification is started; and the PT wire breakage identification judging module judges whether the PT wire breakage identification meets the judging condition, and if so, the PT wire breakage alarm signal is sent in a delayed mode, and the synchronous closing and the non-voltage closing are detected in a locking mode.
Further, the intelligent substation comprises an entity measurement and control module and a cluster measurement and control module, each virtual measurement and control unit in the cluster measurement and control module corresponds to each entity measurement and control unit in the entity measurement and control module one by one, and when the entity measurement and control unit fails, the intelligent substation is automatically switched to the corresponding virtual measurement and control unit in the cluster measurement and control module according to the interval 1 to 1. Specifically, as shown in fig. 5, the intelligent substation measurement and control function adopts a mode of single-interval entity measurement and control and cluster measurement and control, each virtual measurement and control unit in the cluster measurement and control corresponds to the single-interval entity measurement and control unit of the intelligent substation one by one, and when the entity measurement and control unit fails, the corresponding virtual measurement and control unit in the cluster measurement and control is automatically switched to according to interval 1 to 1. The cluster measurement and control module can simultaneously operate a plurality of virtual measurement and control modules, and the virtual measurement and control modules are backups of the entity measurement and control modules and are put into operation only when the entity measurement and control modules are in fault or abnormal. The virtual measurement and control module uses ICD model, CID configuration, interlocking rule and operation parameters of the entity measurement and control device. When the virtual measurement and control module starts to operate, the communication parameters, the IP address, the multicast address, the APPID of the process layer GOOSE control block and the like of the entity measurement and control module are used, so that a client communicating with the virtual measurement and control module can regard the client as the original entity measurement and control module.
In summary, the invention provides a method and a device for identifying PT broken lines of an intelligent substation, wherein the method comprises the steps of collecting bus voltages of all sections, currents of all intervals of bus section wiring, positions of all intervals of circuit breakers and positions of the section circuit breakers in real time; judging whether to start the PT disconnection recognition of the voltage transformer according to preset conditions; judging whether PT wire breakage identification meets a judging condition, if so, sending PT wire breakage alarm signals in a delay mode, and locking and detecting synchronous closing and non-voltage closing. The invention adopts the multi-interval voltage and current quantity comprehensive discrimination collected by the cluster measurement and control device, identifies PT broken lines according to the characteristics of PT broken lines and system faults, can discriminate according to the voltage on another section of bus in parallel operation, additionally introduces other interval currents on the same bus to assist discrimination, locks PT broken line discrimination when the current changes, solves the problem of false report or incorrect identification of PT broken lines, and improves the reliability of PT broken line identification.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explanation of the principles of the present invention and are in no way limiting of the invention. Accordingly, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present invention should be included in the scope of the present invention. Furthermore, the appended claims are intended to cover all such changes and modifications that fall within the scope and boundary of the appended claims, or equivalents of such scope and boundary.
Claims (8)
1. The intelligent transformer substation PT disconnection recognition method is characterized by comprising the following steps of;
collecting the busbar voltage of all the sections, the current of all the intervals of busbar section wiring, the positions of all the interval circuit breakers and the positions of the section circuit breakers in real time;
judging whether to start the PT disconnection recognition of the voltage transformer according to preset conditions;
if the preset condition is met, PT disconnection identification is started; otherwise, continuing to perform the step of real-time acquisition;
if the PT disconnection identification meets the judgment condition, a PT disconnection alarm signal is sent in a delayed mode, and synchronous closing and non-voltage closing are closed; otherwise, continuing to perform the step of real-time acquisition;
the preset conditions for starting the voltage transformer PT disconnection recognition include:
U Φ1 (t-2T)-U Φ1 (t)＞0.1U N (1)
if the formula (1) is established, starting the voltage transformer PT disconnection recognition;
wherein U is Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U Φ1 (T-2T) is A, B, C phase voltage amplitude two weeks before the bus where PT is located when the disconnection is started; u (U) N The PT secondary rated value;
the PT disconnection recognition comprises the following steps of sequentially judging: (1) The positive sequence voltage, the negative sequence voltage or the zero sequence voltage of the bus where the PT is located, and the positions of all the circuit breakers at intervals or whether current exists on the bus where the PT is located; (2) PT broken lines identify whether all interval currents on the bus change or not when the PT broken lines are started; (3) And judging the position of the sectionalized breaker, and judging whether the sectional bus voltage values are different when the sectionalized breaker is in a closing position.
2. The intelligent substation PT disconnection recognition method of claim 1, wherein determining the value of positive sequence voltage, negative sequence voltage or zero sequence voltage of the bus where the condition (1) PT is located, and the positions of all the circuit breakers at intervals or whether there is current on the bus where the PT is located, includes:
judging whether any phase voltage of a bus where PT is located is low and positive sequence voltage is low and whether current or a breaker is in a closing position at any interval of the corresponding bus, or whether PT has negative sequence voltage or zero sequence voltage, wherein a judgment equation is as follows:
or (b)
U 2.1 (t)＞0.1U N (3)
Or (b)
3U 0.1 (t)＞0.1U N (4)
If one of the formulas (2), (3) or (4) is satisfied, continuing to judge the judging condition (2), otherwise, ending the judgment of PT disconnection recognition;
wherein U is Φ1 (t) is the A, B, C phase voltage amplitude of the bus where PT is located when PT disconnection identification is started, U 1.1 (t) is positive sequence voltage amplitude of bus where PT is located when PT wire breakage identification is started, U 2.1 (t) is the negative sequence voltage amplitude of the bus where PT is located when PT wire breakage identification is started, U 0.1 (t) is the zero sequence voltage amplitude of the bus where PT is located when PT wire breakage identification is started, I Φ1 (t) A, B, C phase current amplitude corresponding to any interval of the bus at the start of PT wire breakage identification, and DL is the position of the breaker corresponding to any interval of the bus at the start of PT wire breakage identification; i N And protecting the CT secondary rated value for the corresponding bus.
3. The intelligent substation PT disconnection recognition method of claim 1, wherein determining whether there is a change in all of the gap currents on the bus bar at the start of the PT disconnection recognition of condition (2) includes:
when PT wire breakage identification is started, zero sequence current does not exist at all intervals of corresponding buses, phase current does not change, and a discrimination equation is as follows:
if the above formula (5) is satisfied, continuing to judge the judging condition (3), otherwise, ending the judgment of PT disconnection recognition;
i in the above Φ1 (t) is the A, B, C phase current amplitude of any interval corresponding to the bus when PT disconnection recognition is started, I Φ1 (T-2T) is A, B, C phase current amplitude which is two weeks before the corresponding bus interval when PT disconnection is started, I 0.1 (t) is the three-phase self-produced zero-sequence current amplitude corresponding to the bus interval during the disconnection starting, I N And protecting the CT secondary rated value for the corresponding bus.
4. The intelligent substation PT disconnection recognition method of claim 1, wherein the determining condition (3) determines the position of the sectionalized breaker, determines whether the sectional bus voltage values are different at the closing position, includes:
if the sectional circuit breaker is at a closing position, the amplitudes of bus voltages at two sides of the sectional circuit breaker are the same, the other section of bus PT has no zero sequence voltage and no negative sequence voltage when PT is disconnected, the amplitudes of the two sections of bus voltages are different, and a discrimination equation is as follows:
if the above formula (6) is satisfied, sending a PT disconnection warning signal, otherwise, ending the judgment of PT disconnection recognition;
wherein U is 2.2 (t) is the negative sequence voltage amplitude of the other bus section when the disconnection is started, U 0.2 (t) is the zero sequence voltage amplitude of another bus at the time of starting the disconnection, U Φ1 (t) PT wire breakageIdentifying A, B, C phase voltage amplitude of bus where PT is located during starting, U Φ2 (t) is A, B, C phase voltage amplitude of another bus at break starting, U N The PT secondary rated value;
if the sectional breaker is not at the closing position, the PT wire breakage alarm signal is directly sent.
5. The intelligent substation PT disconnection recognition method of any of claims 1-4, wherein the time-delay sending the PT disconnection warning signal includes time-delay 10s sending the PT disconnection warning signal.
6. The intelligent substation PT disconnection recognition apparatus, which performs PT disconnection recognition judgment according to the intelligent substation PT disconnection recognition method of any one of claims 1 to 5, comprising:
the collecting module is used for collecting the voltages of all the sectional buses, currents at all intervals of bus sectional wiring, the positions of all the interval circuit breakers and the positions of the sectional circuit breakers in real time;
the PT wire breakage identification starting judgment module judges whether to start the PT wire breakage identification of the voltage transformer according to preset conditions; if the preset condition is met, PT disconnection identification is started;
and the PT wire breakage identification judging module judges whether the PT wire breakage identification meets the judging condition, and if so, the PT wire breakage alarm signal is sent in a delayed mode, and the synchronous closing and the non-voltage closing are detected in a locking mode.
7. The intelligent substation PT disconnection recognition device according to claim 6, wherein the intelligent substation comprises an entity measurement and control module and a cluster measurement and control module, each virtual measurement and control unit in the cluster measurement and control module corresponds to each entity measurement and control unit in the entity measurement and control module one by one, and when the entity measurement and control unit fails, the intelligent substation is automatically switched to the corresponding virtual measurement and control unit in the cluster measurement and control module according to the interval 1 to 1.
8. The intelligent substation PT disconnection recognition apparatus of claim 7, wherein the virtual measurement and control unit uses ICD model, CID configuration, interlock rules and operating parameters of the physical measurement and control unit; when the virtual measurement and control unit starts to operate, the communication parameters, the IP address, the multicast address and the APPID of the process layer GOOSE control block of the entity measurement and control unit are used.
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| CN115032498A (en) * | 2022-06-06 | 2022-09-09 | 北京四方继保工程技术有限公司 | Line protection PT disconnection identification method and system based on voltage change trend and continuous current change characteristics |
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