CN113884942B - SCADA data-based grounding line selection alarm correctness checking method - Google Patents
SCADA data-based grounding line selection alarm correctness checking method Download PDFInfo
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Abstract
The invention discloses a method for checking the correctness of a grounding line selection alarm based on SCADA data, which comprises the following steps: the SCADA acquires various data in real time; the SCADA searches whether a bus grounding signal exists, if so, whether the bus grounding signal is a first bus grounding signal sent by a substation low-current grounding line selection device or a second bus grounding signal calculated by the SCADA itself is judged; if the first bus grounding signal is the first bus grounding signal, the SCADA searches the self grounding judgment condition in a first preset time for receiving the first bus grounding signal, and compares whether the first bus grounding signal exists or not; and if the signal is the second bus grounding signal, the SCADA retrieves the received various data and compares whether the second bus grounding signal exists or not in a second preset time when the second bus grounding signal is received. The invention can verify the correctness of the grounding line selection signal of the low-current grounding line selection device at the current power station end so as to improve the accuracy of the grounding line selection alarm of the device and facilitate the improvement of the device.
Description
Technical Field
The invention relates to a ground connection route selection alarm correctness checking method based on SCADA data, and belongs to the technical field of ground faults of power systems.
Background
In actual operation, single-phase or three-phase grounding faults often occur to bus and line of the power system, and particularly, the grounding faults of the bus and the line occur more frequently under severe weather conditions such as rainy season, strong wind, hail and the like. In addition, small current ground faults caused by small animals, tree barriers and the like also frequently occur. The current low-current grounding line selection device of the transformer substation can only be used for detecting single-phase grounding faults, and has the problems of device faults, grounding false alarms and the like. In addition, the condition that the device is dead, the program is blocked, and the like, which causes the floor drain to send out and report missing also happens sometimes.
Disclosure of Invention
Based on the above, the invention provides a ground line selection alarm correctness checking method based on SCADA data, which can verify the correctness of the ground line selection signal of the low-current ground line selection device at the current power station end so as to improve the accuracy of the ground line selection alarm of the device, and simultaneously, the device is convenient to improve so as to overcome the defects of the prior art.
The technical scheme of the invention is as follows: the method for checking the correctness of the grounding line selection alarm based on SCADA data comprises the following steps:
the method comprises the steps that SCADA collects various data in real time, the SCADA is distributed at a power dispatching end, the various data are data of a power plant station end, the SCADA is in communication connection with the power plant station end, and the power plant station end is provided with a substation small current grounding line selection device;
the SCADA searches whether a bus grounding signal exists, if so, whether the bus grounding signal is a first bus grounding signal sent by the substation low-current grounding line selection device or a second bus grounding signal calculated by the SCADA itself is judged;
if the first bus grounding signal is the first bus grounding signal, the SCADA searches for self grounding judgment conditions in a first preset time when the first bus grounding signal is received, compares whether the first bus grounding signal exists or not, and counts whether the small current grounding line selection device of the transformer substation is correct or not according to the comparison conditions;
and if the signal is a second bus grounding signal, the SCADA retrieves the received various data within a second preset time of receiving the second bus grounding signal, compares whether the second bus grounding signal exists or not, and counts whether the low-current grounding line selection device of the transformer substation is correct or not according to the comparison condition.
Optionally, if the first bus grounding signal exists, determining that the first bus grounding signal is correct, and performing SCADA statistics on the correct number of times of the substation low-current grounding line selection device under the substation low-current grounding line selection device to be i=i+1; if the first bus grounding signal does not exist, the SCADA searches for the self grounding judgment condition in a third preset time for receiving the first bus grounding signal, and compares whether the first bus grounding signal exists or not; if the first bus grounding signal still does not exist, judging that the first bus grounding signal is incorrect, and carrying out SCADA statistics on false alarm times of the substation low-current grounding line selection device to be j=j+1; at this time, if the first bus grounding signal exists, it is determined that the first bus grounding signal is correct, but the delay is determined, the accuracy is not high, and the SCADA counts the time delay k=k+1 for the substation low-current grounding line selection device.
Optionally, if the second bus grounding signal exists, determining that the second bus grounding signal is correct, and performing SCADA statistics on correct times on pairs of the substation low-current grounding line selection device to obtain m=m+1; if the second bus grounding signal does not exist, the SCADA retrieves the received various data and compares whether the second bus grounding signal exists or not in a fourth preset time when the second bus grounding signal is received; if the second bus grounding signal still does not exist, judging that the substation small-current grounding line selection device has no bus grounding signal, and carrying out SCADA statistics on the leakage report frequency of the substation small-current grounding line selection device to be h=h+1; and if the second bus grounding signal exists, judging that the bus grounding signal of the substation small-current grounding line selection device is correct, judging that time delay exists, and counting the time delay times k=k+1 on the substation small-current grounding line selection device by SCADA, wherein the time delay is not high.
Optionally, the second bus grounding signal is obtained by periodically calculating SCADA according to the various data, and the bus grounding calculation method comprises a single-phase grounding starting criterion, a bus grounding disconnection judging method and a grounding fault judging method through a small-resistance grounding system.
Optionally, the single-phase grounding starting criterion is that the zero sequence voltage of a bus in the main network system, the three-phase power grid of the bus, the grounding alarm of a line and the logic AND or non-combination of a scene of a wave recording blocking or wave recording starting signal in the distribution network system are used as the single-phase grounding starting criterion, in the periodic calculation, the set number of times of calculation is started, if the calculation results are all true, the bus is judged to be grounded, otherwise, the bus is judged to be not grounded.
Optionally, for the bus open-phase, the bus open-phase determining method includes:
if the voltage of the grounding phase bus is smaller than a first preset value and the voltages of the non-grounding phase bus are all larger than a second preset value, judging that the bus is out of phase; or the absolute value of the difference between any two phases of the bus voltage is larger than a third preset value, and judging that the bus is out of phase; or any one voltage of the bus voltage is smaller than a fourth preset value, and when at least one phase of the two phases of voltages is larger than a fifth preset value, judging that the bus is out of phase;
for bus grounding, the bus grounding judgment method comprises the following steps:
if the bus voltage grounding phase is smaller than the sixth preset value and the non-grounding phase voltages are all larger than the seventh preset value, judging that the bus is grounded; or if the voltage of any one phase of the bus voltage is larger than the eighth preset value and the absolute value of the difference between the voltages of the two phases is larger than the ninth preset value, judging that the bus is grounded.
Optionally, the method for judging the ground fault of the grounding system through the small resistor is to analyze the current direction of each line on the same bus according to the real-time data calculated by the tide, wherein the current direction of the fault line is opposite to that of other non-fault lines, so as to judge the fault line.
Optionally, the various data includes bus voltage, line current and signals sent by the line protection device.
Optionally, a verification method is operated according to a preset period, and the number h of missed reports, the number i of correct lower reports, the number j of false reports, the number k of delay lower reports, the number m of correct upper reports and the number n of delay upper reports of the low-current grounding line selection device are counted.
The beneficial effects of the invention are as follows: the invention collects and analyzes various data of the power station end in real time through the SCADA, and can accurately calculate whether the grounding route selection of the current station end small current grounding route selection device is correct or not after judging whether the bus grounding signal is from the small current grounding route selection device or the SCADA calculates itself, further calculates the annual/month availability, the accuracy, the error event record statistics analysis and the like of the small current grounding route selection device, is a more efficient and convenient processing scheme or means for timely finding problems of the small current grounding route selection device and determining the positions which need to be improved, and particularly has smaller false alarm and error action probability based on the SCADA full data.
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FIG. 1 is a flow chart of a method according to an embodiment of the present invention;
FIG. 2 is a functional architecture diagram of an embodiment of the present invention;
fig. 3 is a schematic diagram of an embodiment of the present invention.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit or scope of the invention, which is therefore not limited to the specific embodiments disclosed below.
Referring to fig. 1 to 3, the method for checking the correctness of the ground line selection alarm based on SCADA data in this embodiment includes:
s1, SCADA collects various data in real time, the SCADA is distributed at a power dispatching end, the various data are data of a power plant station end, the SCADA is in communication connection with the power plant station end, and the power plant station end is provided with a substation small current grounding line selection device.
The SCADA (system) is arranged at the power dispatching end and comprises modules such as SCADA data processing and monitoring, front-end acquisition, network topology, load prediction, short-circuit current calculation, dispatcher power flow and state estimation and the like, wherein the SCADA data processing and monitoring serve as a main control module and are respectively and electrically connected with the front-end acquisition, network topology, load prediction, short-circuit current calculation, dispatcher power flow and state estimation and the like, the front-end acquisition module is in communication connection with a remote control module of the power plant station end, and not only can various data of the power plant station end be received through the remote control module, but also control information can be transmitted to the power plant station end for execution through the remote control module.
The following explains the above functional modules:
SCADA system: data acquisition, data processing, data monitoring and data real-time monitoring control.
Front acquisition: the system is mainly in communication connection with a remote control module at a station end and is used for collecting various data, transmitting command information and the like.
Network topology: and the electric island connection relation formed by all the substations in the area and the electric connection relation formed by the inside of each substation.
State estimation: and (3) State Estimation (SE) which gives the optimal estimated value of each busbar voltage (amplitude and phase) and tide in the power grid according to the real-time information provided by the SCADA. The state estimation is analyzed and calculated according to the SCADA real-time remote signaling telemetry data, so that a relatively accurate and complete operation mode is obtained, and all bus voltages and all load sizes can be calculated. And meanwhile, checking the remote signaling telemetry of the SCADA, providing telemetry points which are possibly abnormal, and returning the calculation result and the measurement quality mark to the SCADA. The calculation result of the state estimation can be used by other application software as a real-time mode, for example, dispatcher tide can carry out simulation operation calculation and the like based on the calculation result of the state estimation.
Dispatcher tide: dispatcher tide is one of the most basic applications of PAS. The mode can be adjusted at any time through online tide calculation, so that the active power distribution is more reasonable. By using the estimated data to perform power flow calculation, a scheduler can arrange theoretical basis for future modes, and the power flow calculation method is more accurate, more reliable and more truly reflects the power grid state than off-line calculation. In the switching operation and accident handling process, the dispatcher tide can play a good role in assisting decision making. Dispatcher power flow is a comprehensive application, and comprises several sub-applications, such as dispatcher power flow, short circuit calculation, static safety analysis and reactive power optimization. Each sub-application has its own independent picture and its own independent main picture. The relation and data flow among the modules are introduced in the offline analysis picture, firstly, the offline analysis software (dispatcher tide, static safety analysis, short circuit calculation and reactive power optimization) acquires the latest power grid model, and then acquires the historical section after acquiring the power grid model, and a plurality of modes are available for acquiring the section, such as taking the historical section, taking the real-time section, taking the historical whole-point section and the like. After the power grid model and the section are acquired, offline analysis software can be used for calculation, and the calculated results can be displayed on different pictures.
Load prediction: the function of load prediction is: future loads of the user-defined predicted measure points are predicted.
Short circuit current calculation: the short-circuit current calculation is to correct an overcurrent generated when a short circuit is caused in a circuit due to a fault or a connection error. The current that flows when an abnormal connection (short circuit) occurs between phases or between phases and ground (or neutral) in the power system during operation is called a short circuit current. The basic types of short circuits that occur in a three-phase system are three-phase short circuits, two-phase short circuits, single-phase to ground short circuits, and two-phase to ground short circuits. The three-phase short circuit is called a symmetrical short circuit because the three-phase loop is still symmetrical when in short circuit; the other types of short circuits are known as asymmetric short circuits, because they make the three-phase circuit asymmetric. In a grid with a neutral point directly grounded, short-circuit faults with respect to the ground are the most, which account for about 90% of all short-circuit faults. In a power network where the neutral point is not directly grounded, short-circuit faults are mainly various phase-to-phase short-circuits. When a short circuit occurs, the current in the short circuit loop is greatly increased, possibly many times exceeding the rated current of the loop, due to the decrease in the impedance of the power supply loop of the power supply and the transient course in the event of a sudden short circuit. The magnitude of the short-circuit current depends on the electrical distance of the short-circuit point from the power supply, for example, when a short-circuit occurs at the generator end, the maximum instantaneous value of the short-circuit current flowing through the generator can reach 10 to 15 times the rated current of the generator, and in a large-capacity power system, the short-circuit current can reach tens of thousands of amperes.
Dispatcher training and simulation: the dispatcher training simulation (Dispatcher Training Simulator, DTS for short) can provide a comprehensive power system simulation tool for the dispatcher to train, check and conduct anti-accident exercise so as to improve the professional level and working skill of the power grid dispatching and management personnel; in addition, the device is also used as an analysis research tool for power grid operation, support and decision-making personnel. The training function mainly comprises power grid dispatching operation control simulation training and EMS system application operation simulation training. The dispatcher training simulation system can simulate various running states of the power system, including a normal state, an emergency state, a fault state and an accident recovery process, so that students can perform normal operation, accident handling and system recovery training in the dispatching environment which is completely the same as an actual dispatching center, various functional modules of the EMS are mastered, various operations are familiar, and the change condition of the system is experienced with high fidelity while observing the system state and implementing control measures.
Automatic reactive power control: the AVC program runs in regional dispatching centers, transformer substations and centralized control stations, mainly controls the voltage and reactive power of regional power grids, transformer substations and centralized control stations, contains an automatic control strategy in software, supports a user to control a 9-area diagram or a 17-area diagram, and increases and decreases related locking conditions. Topology analysis is required to be performed during each operation, so that control is more reliable. The AVC program may run on multiple nodes, but typically runs on two hosts, one standby on duty, commanded by the airliners, which synchronize the attendant information. And when the airliner fails, the standby machine is automatically upgraded to an on-duty node.
In the SCADA system, the voltage of each central point is analyzed in real time through real-time tide calculation data, the voltage change of each bus of the whole network is analyzed, and the buses of abnormal phase voltage and abnormal zero sequence voltage are identified. And (3) carrying out real-time analysis on the grounding of one bus on the network by utilizing network topology calculation, wherein the grounding of each 220kV bus which is connected with the bus in the whole network and the grounding of other 220kV transformer substation areas, 110kV transformer substation areas and 35kV transformer substation areas which are connected with the 220kV bus possibly occur, sending out emergency alarm according to the possible area grounding event, positioning out a grounding Siamese or grounding bus, executing a remote control breaker, timely cutting off a grounding line, and carrying out round cutting if necessary. And (3) estimating the total station, even the total network voltage and current or P, Q change caused by the change of the bus voltage in a certain transformer substation by using state estimation, and the total station and total network load change caused by the closing and opening of the circuit breaker in the ground fault elimination process. And (3) carrying out grounding simulation on fault points which are possibly grounded by buses/lines in the whole network by using a dispatcher training simulation system (DTS), so as to realize overall process simulation of 'fault definition-fault generation-fault analysis-fault judgment-fault analysis processing-fault removal' of the buses/lines, and realize line selection and line pulling or round cutting simulation after the buses/lines are grounded in a simulation environment. The fault (post) analysis method of accident inversion (PDR) and SOE is utilized, and the accident inversion (PDR) provides analog quantity change before, during and after the occurrence of the accident of the power system. SOE provides hard contact signals or soft contact signals of a transformer substation, and comprises signals such as a switch, a disconnecting link deflection, a line protection action and the like, such as a protection action, a reclosing action, a PT disconnection, a device call, a switching relay simultaneous action, a switch trip, a switch closing position, a control loop disconnection, a spring non-energy storage and the like. According to the analysis method, the trip closing time point of the circuit breaker and the obvious change time point of the analog quantity are found through the unified time scale, the sequence of actions, namely the change of the analog quantity, at the key time node is analyzed, and the possible cause of the occurrence of the fault event is analyzed.
According to the invention, the scada system collects remote signaling and remote measurement of the transformer substation in real time, and has a remote control function on a switch of the transformer substation. The remote signaling comprises a hard contact and soft message of protection, SOE of a switch and remote signaling deflection signals, the remote sensing comprises a SCADA and a PAS applied real-time section, and remote signaling and remote sensing data provide abundant data sources for real-time diagnosis of bus/line grounding. Real-time PAS and SCADA models provide a complete power grid model for real-time diagnosis of bus/line grounding and automatic recovery of ground faults. The Scada system provides decisions and decision execution for judging the ground fault and automatically processing and recovering the ground fault through real-time diagnosis of bus/line grounding and remote control function of a station switch.
The various data include bus voltage, line current, line protection device and signal sent by small current grounding line selection device. In particular, the busbar voltages comprise line voltages Uab, ubc, uca, phase voltages Ua, ub, uc, zero sequence voltages Uo; line voltages include, but are not limited to Ua, ub, uc, uab, ubc, uca, U, uo, 3Uo; line currents include, but are not limited to Ia, ib, ic, iab, ibc, ica, io, 3Io; the signals sent by the line protection device comprise signals such as an overcurrent one-stage action, an overcurrent two-stage action, a zero sequence voltage action, a protection action, a primary/secondary reclosing action and the like; the signal sent by the low-current grounding line selection device comprises a bus grounding signal.
S2, the SCADA searches whether a bus grounding signal exists, and if so, whether the bus grounding signal is a first bus grounding signal sent by the substation low-current grounding line selection device or a second bus grounding signal calculated by the SCADA.
Specifically, the SCADA retrieves in real time or periodically whether there is a bus-bar ground signal, and determines whether the bus-bar ground signal is sent from the substation low-current ground line selection device or the SCADA itself is calculated so as to select a verification scheme.
The SCADA periodically calculates all bus grounding conditions in the whole power grid according to various data, and the bus grounding calculation method comprises a single-phase grounding starting criterion, a bus grounding breaking judgment method and a grounding fault judgment method through a small-resistance grounding system.
The single-phase grounding starting criterion is that the zero sequence voltage of a bus in a main network system, a bus three-phase power grid, a bus grounding alarm, a line grounding alarm and a logic AND or non-combination of a scene of a wave recording blocking or wave recording starting signal in a distribution network system are used as the single-phase grounding starting criterion, in periodic calculation, the set times of starting calculation are calculated, if the calculation results are all true, the bus is judged to be grounded, otherwise, the bus is judged to be ungrounded.
Specifically, the single-phase grounding starting criterion refers to that a logic AND or non-combination of a 10kV/35kV bus zero sequence voltage (3U 0), a 10kV/35kV bus three-phase power grid (Ua/Ub/Uc), a 10kV/35kV bus grounding alarm and a 10kV/35kV line grounding alarm in a main network system and a logic AND or non-combination of a wave recording blocking or wave recording starting signal in a distribution network system passing through a scene are used as the starting criterion of the single-phase grounding. Examples: condition 1: x1 represents the zero sequence voltage (3U 0) of a main network 10kV bus, and the condition 2 is as follows: x2 represents the phase A voltage of the 10kV bus of the main network, and the condition 3 is as follows: x3 represents the phase B voltage of the 10kV bus of the main network, and the condition 4 is as follows: x4 represents the C-phase voltage of the 10kV bus of the main network, and the condition 5 is as follows: x5 represents a main network 10kV bus grounding alarm action, and condition 6: x6 represents the signal action of 'recording blocking' or 'recording starting' in the distribution network system, and the 10kV single-phase grounding starting conditional expression is as follows: x1>30| ((x 2<4.8 &x3>7.0 &x4> 7.0) | (x 2>7.0 &x3<4.8& x4> 7.0) | (x 2>7.0 &x3>7.0 &x4< 4.8))|x5|x6, and so on, the 35kV single phase ground start conditional expression is: x1>30| ((x 2<16.0 &x3>24.5& & x4> 24.5) | (x 2>24.5& & x3 <). 16.0& & x4> 24.5) | (x 2>24.5& & x3>24.5& & x4< 16.0) |x5|x6. In the acquisition period, 3 times of calculation are started, the calculation results of the 3 expression are all true, namely the calculation result is true, and the bus is judged to be grounded; if the calculation result of at least one expression is not true in the continuous 3 times of calculation, that is, the calculation result is false, the bus is judged not to be grounded.
For bus phase failure, the bus phase failure judging method comprises the following steps: if the voltage of the grounding phase bus is smaller than a first preset value and the voltages of the non-grounding phase bus are all larger than a second preset value, judging that the bus is out of phase; or the absolute value of the difference between any two phases of the bus voltage is larger than a third preset value, and judging that the bus is out of phase; or any one voltage of the bus voltage is smaller than a fourth preset value, and when at least one phase of the two phases of voltages is larger than a fifth preset value, judging that the bus is out of phase.
In the following expression, x1 is a Ua real-time value, x2 is a Ub real-time value, and x3 is a Uc real-time value.
Examples: the bus phase failure is calculated and used as auxiliary calculation of bus grounding, and the specific method is as follows:
10kV bus phase failure:
(x 1<4.5& x2>5.3& x3> 5.3) | (x 2<4.5& x1> 5.3) | (x 3<4.5& x1> 5.3) | (x 2) 5.3) or (x 1<4.5 > (x 2) 5.3| (x 3) is determined to be less than 4.5kV when the voltage of the non-grounded phase bus is greater than 5.3kV, or (abs (x 1-x 2) > 0.5) | (abs (x 2-x 3) > 0.5) (i.e., the absolute value of the difference between any two phases of the 10kV bus is greater than 0.5 kV) (or (x 1<4.5 > (x 2) 5.3) 3) is determined to be greater than the voltage of the non-grounded phase bus (x 1<4.5 kV) (x 2.3) and (x 2.3) is determined to be greater than the voltage of at least 4.3 kV (x 1-x 3) 2.5) is determined to be greater than the voltage of any two phases (x 1-x 3) (i.3) 3) if the voltage of the non-grounded phase bus is greater than 5.3kV (x 2) is greater than the voltage of any two phases (x 2.3).
35kV bus phase failure:
(x 1<15& (x 2>19 |x3> 19)) | (x 2<15& (x 1>19||x3> 19)) | (x 3<15& (x 1>19||x2> 19)) (i.e. when the voltage of either phase of the 35kV bus is less than 15kV, if at least one phase of the other two phases is greater than 19kV, the 35kV bus is determined to be out of phase).
For bus grounding, the bus grounding determination method comprises the following steps: if the bus voltage grounding phase is smaller than the sixth preset value and the non-grounding phase voltages are all larger than the seventh preset value, judging that the bus is grounded; or if the voltage of any one phase of the bus voltage is larger than the eighth preset value and the absolute value of the difference between the voltages of the two phases is larger than the ninth preset value, judging that the bus is grounded.
Examples: the specific method for calculating the bus grounding is as follows:
10kV bus grounding:
(x 1>6.3& x2>6.3& x3< 5.2) | (x 1>6.3& x3>6.3& x2< 5.2) | (x 2>6.3& x3>6.3& x1< 5.2) (i.e. when the 10kV bus voltage ground phase is less than 5.2kV and both non-ground phase voltages are greater than 6.3kV, the 10kV bus ground is determined), or ((x 1> 6.5) & abs (x 2-x 3) > 0.6) | ((x 2> 6.5) & abs (x 1-x 3) > 0.6) | () & s (x 3> 6.5) & abs (x 1-x 2) & gt 0.6) (i.6) when either phase voltage of the 10kV bus voltage is greater than 6.5kV, the 10kV bus ground is determined if the absolute value of the difference between the other two phase voltages is greater than 0.6 kV).
35kV bus grounding:
(x 1>23& x2>23& x3< 18) | (x 1>23& x3>23& x2< 18) | (x 2>23& x3>23& x1< 18) (i.e., 35kV bus voltage is less than 18kV when either phase bus voltage is greater than 23kV and both other phases are greater than 23kV, the 35kV bus is determined to be grounded), or x1>26||x2> 26|x3 >26||abs (x 1-x 2) > 10.5|abs (x 1-x 3) > 10.5|abs (x 2-x 3) >10.5 (i.e., 35kV bus voltage is determined to be grounded when either phase bus voltage is greater than 26kV, or the absolute value of the difference between either phase is greater than 10.5 kV).
When the grounding occurs through the small-resistance grounding system, the fault line current direction (the direction of Io) is opposite to the non-fault line current direction, namely positive and negative. The method for judging the grounding fault of the grounding system through the small resistor is to analyze the current directions of all lines on the same bus according to the real-time data calculated by the tide, wherein the current directions of the fault line and other non-fault lines are opposite, and therefore the fault line is judged.
The Scada system is simultaneously provided with the three bus/line grounding calculation methods, and a certain or a plurality of combination calculation methods are selected during specific operation, and are selectable through a human-computer interface.
And S3, if the signal is a first bus grounding signal, the SCADA searches self grounding judgment conditions in a first preset time when the first bus grounding signal is received, compares whether the first bus grounding signal exists or not, and counts whether the small current grounding line selection device of the transformer substation is correct or not according to the comparison conditions.
Specifically, if the bus grounding signal is determined to be the first bus grounding signal sent by the substation low-current grounding line selection device, the SCADA searches the self grounding determination condition within the time range of time scale + -1 min of receiving the first bus grounding signal, compares and determines whether the first bus grounding signal exists, if the first bus grounding signal is compared and determined to exist, then determines that the first bus grounding signal is correct, and the SCADA counts the next correct times of the substation low-current grounding line selection device to be i=i+1. If the first bus grounding signal is judged to be absent, the SCADA searches the self grounding judgment condition within the time range of + -5 min of the time scale of receiving the first bus grounding signal, and compares and judges whether the first bus grounding signal is present or not; if the first bus grounding signal still does not exist, judging that the first bus grounding signal is incorrect, and counting false alarm times of a small-current grounding line selection device of the substation by SCADA to be j=j+1; at this time, if the first bus grounding signal exists, the first bus grounding signal is judged to be correct, but delay is judged to exist, the accuracy is not high, and the SCADA counts the time k=k+1 of the delay time of the substation low-current grounding line selection device.
And S4, if the signal is a second bus grounding signal, the SCADA retrieves the received various data within a second preset time when the second bus grounding signal is received, compares whether the second bus grounding signal exists or not, and counts whether the small-current grounding line selection device of the transformer substation is correct or not according to the comparison condition.
Specifically, if the bus grounding signal is determined to be calculated by the SCADA, the SCADA searches the received low-current grounding line selection device signal within the time range of +/-1 min of the time scale of judging the grounding by the SCADA, and compares whether the second bus grounding signal is received or not. And if the second bus grounding signal is received, judging that the second bus grounding signal is correct, and carrying out SCADA statistics on correct times on the small-current grounding line selection device of the transformer substation to be m=m+1. If the second bus grounding signal is not received, the scada searches the received low-current grounding line selection device signal within the time range of +/-5 min of the time scale of judging the grounding by the scada, and compares whether the second bus grounding signal is received or not; if the second bus grounding signal is still not received, judging that the substation small-current grounding line selection device has no bus grounding signal, and carrying out SCADA statistics on the number of times of leakage report of the substation small-current grounding line selection device to be h=h+1; and if the second bus grounding signal is received, judging that the bus grounding signal of the substation small-current grounding line selection device is correct, and judging that the delay exists, wherein the accuracy is not high, and the SCADA counts the up-delay times k=k+1 of the substation small-current grounding line selection device.
Optionally, a verification method is operated according to a preset period, and the number h of missed reports, the number i of correct lower reports, the number j of false reports, the number k of delay lower reports, the number m of correct upper reports and the number n of delay upper reports of the low-current grounding line selection device are counted. Specifically, the above calculation is run periodically. According to the annual, monthly and daily statistics of the number h of missed reports of the low-current grounding line selection device, the number i of lower correct times, the number j of false reports, the number k of lower delay times, the number m of upper correct times and the number n of upper delay times, the grounding judgment delay rate, the missing report rate, the false report rate, the error event record and the like of the low-current grounding line selection device of each transformer substation/each quarter and the like are calculated according to requirements.
The invention collects and analyzes various data of the power station end in real time through the SCADA, and can accurately calculate whether the grounding route selection of the current station end small current grounding route selection device is correct or not after judging whether the bus grounding signal is from the small current grounding route selection device or the SCADA calculates itself, further calculates the annual/month availability, the accuracy, the error event record statistics analysis and the like of the small current grounding route selection device, is a more efficient and convenient processing scheme or means for timely finding problems of the small current grounding route selection device and determining the positions which need to be improved, and particularly has smaller false alarm and error action probability based on the SCADA full data.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (9)
1. The method for checking the correctness of the grounding line selection alarm based on SCADA data comprises the following steps:
the method comprises the steps that SCADA collects various data in real time, the SCADA is distributed at a power dispatching end, the various data are data of a power plant station end, the SCADA is in communication connection with the power plant station end, and the power plant station end is provided with a substation small current grounding line selection device;
the SCADA searches whether a bus grounding signal exists, if so, whether the bus grounding signal is a first bus grounding signal sent by the substation low-current grounding line selection device or a second bus grounding signal calculated by the SCADA itself is judged;
if the first bus grounding signal is the first bus grounding signal, the SCADA searches for self grounding judgment conditions in a first preset time when the first bus grounding signal is received, compares whether the first bus grounding signal exists or not, and counts whether the small current grounding line selection device of the transformer substation is correct or not according to the comparison conditions;
and if the signal is a second bus grounding signal, the SCADA retrieves the received various data within a second preset time of receiving the second bus grounding signal, compares whether the second bus grounding signal exists or not, and counts whether the low-current grounding line selection device of the transformer substation is correct or not according to the comparison condition.
2. The method for checking the correctness of the ground wire selection alarm based on SCADA data according to claim 1, wherein,
if the first bus grounding signal exists, judging that the first bus grounding signal is correct, and carrying out SCADA statistics on the correct number of times of the substation low-current grounding line selection device in pairs, i=i+1;
if the first bus grounding signal does not exist, the SCADA searches for the self grounding judgment condition in a third preset time for receiving the first bus grounding signal, and compares whether the first bus grounding signal exists or not;
if the first bus grounding signal still does not exist, judging that the first bus grounding signal is incorrect, and carrying out SCADA statistics on false alarm times of the substation low-current grounding line selection device to be j=j+1; at this time, if the first bus grounding signal exists, it is determined that the first bus grounding signal is correct, but the delay is determined, the accuracy is not high, and the SCADA counts the time delay k=k+1 for the substation low-current grounding line selection device.
3. The earth route selection alarm correctness checking method based on SCADA data according to claim 1,
if the second bus grounding signal exists, judging that the second bus grounding signal is correct, and carrying out SCADA statistics on correct times on the substation small current grounding line selection device to be m=m+1;
if the second bus grounding signal does not exist, the SCADA retrieves the received various data and compares whether the second bus grounding signal exists or not in a fourth preset time when the second bus grounding signal is received;
if the second bus grounding signal still does not exist, judging that the substation small-current grounding line selection device has no bus grounding signal, and carrying out SCADA statistics on the leakage report frequency of the substation small-current grounding line selection device to be h=h+1; and if the second bus grounding signal exists, judging that the bus grounding signal of the substation small-current grounding line selection device is correct, judging that time delay exists, and counting the time delay times k=k+1 on the substation small-current grounding line selection device by SCADA, wherein the time delay is not high.
4. The earth route selection alarm correctness checking method based on the SCADA data according to claim 1, wherein the second bus grounding signal is obtained by periodically calculating the SCADA according to the various data, and the bus grounding calculation method comprises a single-phase grounding starting criterion, a bus broken grounding judgment method and a grounding fault judgment method of a grounding system through a small resistor.
5. The method for checking the correctness of the grounding route selection alarm based on SCADA data according to claim 4, wherein the single-phase grounding starting criterion is that a zero sequence voltage of a bus in a main network system, a three-phase power grid of the bus, a bus grounding alarm, a line grounding alarm and a logic AND or non-combination of a scene of a wave recording lock or a wave recording starting signal in a distribution network system are utilized as starting criteria of the single-phase grounding, in periodic calculation, set times calculation is started, if calculation results are all true, the bus is judged to be grounded, otherwise, the bus is judged to be not grounded.
6. The method for checking the correctness of the ground line selection alarm based on SCADA data according to claim 4, wherein for bus phase failure, the bus phase failure judging method comprises the following steps:
if the voltage of the grounding phase bus is smaller than a first preset value and the voltages of the non-grounding phase bus are all larger than a second preset value, judging that the bus is out of phase; or the absolute value of the difference between any two phases of the bus voltage is larger than a third preset value, and judging that the bus is out of phase; or any one voltage of the bus voltage is smaller than a fourth preset value, and when at least one phase of the two phases of voltages is larger than a fifth preset value, judging that the bus is out of phase;
for bus grounding, the bus grounding judgment method comprises the following steps:
if the bus voltage grounding phase is smaller than the sixth preset value and the non-grounding phase voltages are all larger than the seventh preset value, judging that the bus is grounded; or if the voltage of any one phase of the bus voltage is larger than the eighth preset value and the absolute value of the difference between the voltages of the two phases is larger than the ninth preset value, judging that the bus is grounded.
7. The method for checking the correctness of the ground selection line alarm based on SCADA data according to claim 4, wherein the method for judging the ground fault of the grounding system with small resistance is to analyze the current direction of each line on the same bus according to the real-time data calculated by the tide, wherein the current direction of the fault line is opposite to the current direction of other non-fault lines, thereby judging the fault line.
8. The SCADA data-based ground route selection alarm correctness checking method of claim 1 wherein the various types of data comprise bus voltage, line current and signals sent by line protection devices.
9. The method for checking the correctness of the ground selection alarm based on SCADA data according to claim 1, wherein the checking method is operated according to a preset period, and the number h of missed reports, the number i of lower correct reports, the number j of false reports, the number k of lower delay, the number m of upper correct reports and the number n of upper delay of the low-current ground selection device are counted.
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