CN114865619A - Line reactive power abnormity detection method without phase angle - Google Patents

Line reactive power abnormity detection method without phase angle Download PDF

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CN114865619A
CN114865619A CN202210443798.1A CN202210443798A CN114865619A CN 114865619 A CN114865619 A CN 114865619A CN 202210443798 A CN202210443798 A CN 202210443798A CN 114865619 A CN114865619 A CN 114865619A
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line
reactive
loss
deviation
reactive power
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薛安成
顾雷
马婧
景子洋
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North China Electric Power University
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North China Electric Power University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/001—Methods to deal with contingencies, e.g. abnormalities, faults or failures
    • H02J3/0012—Contingency detection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/001—Measuring real or reactive component; Measuring apparent energy
    • G01R21/003—Measuring reactive component
    • 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
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00001—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H02J3/242—Arrangements for preventing or reducing oscillations of power in networks using phasor measuring units [PMU]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/22—Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Human Computer Interaction (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The patent provides a line reactive power abnormity detection method without involving a phase angle. The method does not need a pre-calibrated or high-precision reference transformer, and can realize online detection, thereby ensuring the accuracy of protection setting and state estimation of the power system. Firstly, deducing a line reactive loss model which does not relate to a phase angle, and determining a reactive loss theoretical value when a power transmission line runs; secondly, determining a line PMU/SCADA positive sequence data measurement error limit and an operation parameter deviation limit based on the accurate grade of a line transformer and the actual operation condition of a line; then, determining a reasonable reactive loss deviation amount under a set data error limit and a line parameter deviation limit by combining an error propagation law; and finally, comparing the difference value between the real measured value and the theoretical value of the reactive loss, judging whether the difference value is within a reasonable deviation amount, and outputting the abnormal condition of the line.

Description

Line reactive power abnormity detection method without phase angle
Technical Field
The invention relates to the field of operation control protection of an electric power system, in particular to a line reactive power abnormity detection method without a phase angle.
Background
Currently, PMU data has become one of the important data sources for smart grids. A series of advanced applications have been developed based on PMU/WAMS, such as parameter identification, state estimation, power system monitoring and control, etc. The PMU is characterized by being capable of providing phasor measurement data with consistent time scales, reflecting dynamic response and having smaller time delay; due to the fact that the time mark is accurate, the consistency of the time section can be guaranteed even if the time delay exists in channel transmission. Therefore, the accuracy of PMU data is fundamental to a variety of advanced applications. However, the actual measurement of PMU data on site indicates that a quality problem exists in partial PMU phase angle measurement data, and meanwhile, research indicates that factors such as loss/interference/attack of time synchronization signals, transmission error of a power transformer, PMU algorithm error and the like may cause deviation of the actual PMU data, thereby causing abnormal active and reactive measurement values. It is noted that a Remote Terminal Unit (RTU) based monitoring and data acquisition System (SCADA) is also one of the main data sources of an electrical power system. The SCADA/RTU can measure amplitude and power data, and according to a sampling algorithm, if voltage and current sampling data moments are inconsistent due to the fact that RTU has sampling initial point deviation, sampling point errors and the like, errors can be correspondingly generated in RTU/SCADA active and passive measurement.
Currently, research on detecting and correcting abnormal PMU measurement data mainly focuses on the current, voltage amplitude and phase angle. In the aspect of amplitude, the problems of abnormal data of PMU amplitude are mostly mutation, deletion, continuous bad data and the like; in the phase angle aspect, the problem of PMU phase angle abnormal data is mostly jump, deviation, pull deviation and the like. However, most of the existing methods essentially detect the amount of sudden change of data, and it is difficult to detect a long-term, continuous, and non-sudden measurement error, and many of the methods require a calibrated or highly accurate transformer. In addition, there is no detection method for abnormal power measurement data of PMU/SCADA.
Therefore, the patent provides a method for detecting abnormal reactive measurement of the PMU/SCADA of the line, which does not relate to a phase angle, aiming at the problem of deviation of reactive data measured by the PMU/SCADA, and aims to detect reactive deviation so as to carry out device maintenance or data calibration.
Disclosure of Invention
The invention aims to provide a line reactive power measurement abnormity detection method without involving a phase angle, which deduces and obtains a line reactive power loss reference estimation expression which is irrelevant to the phase angle and is based on PMU/SCADA amplitude measurement and line parameters; furthermore, an online detection method for reactive loss measurement abnormity is provided, and the method can also be used for line single-end reactive loss measurement abnormity detection. Meanwhile, the method does not need a pre-calibrated or high-precision reference transformer, and can realize online detection. The simulation and actual measurement examples verify the effectiveness and practicability of the method.
The technical scheme of the invention is as follows:
a line reactive power abnormity detection method without involving phase angles is characterized by comprising the following steps:
step 1: establishing a line reactive loss model which does not relate to a phase angle, and determining a theoretical value of the line reactive loss;
step 2: determining a PMU/SCADA positive sequence data error limit according to the precision grade of the line transformer; determining a line parameter deviation limit according to the actual operation condition of the line and the actual engineering requirement;
and step 3: determining a reasonable reactive loss deviation amount under a set data error limit and a parameter deviation limit based on an error propagation law;
and 4, step 4: and (3) calculating the deviation of each time section based on the real reactive loss measured value and the theoretical reactive loss value in the step (1), comparing the deviation with the reasonable reactive loss deviation amount of the line in the step (3), and outputting the abnormal condition of the line.
In the step 1, a pi-shaped equivalent model of the power transmission line is established, a line reactive loss expression not related to a phase angle is obtained through theoretical derivation, PMU/SCADA voltage and current amplitude measurement data and a line parameter reference value of a line to be detected are obtained, and a line reactive loss theoretical value is obtained through calculation;
in the step 2, firstly, according to the obtained data type (PMU/SCADA), the precision grade of a measured voltage and a current transformer/high-precision alternating current sampling telemechanical terminal (RTU) is determined, then, the data error limit of the measured PMU/SCADA positive sequence voltage and current is set according to the precision grade, and similarly, according to the actual operation condition of the line and the actual engineering requirement, the deviation limit of the offline value of the line during operation deviating from the true value is set;
and 3, obtaining the amplitude value measurement values of the voltage and the current of the line to be detected, combining the amplitude measurement data error set in the step and the line parameter deviation, and obtaining the reasonable reactive loss deviation amount of the line under the working condition based on the error propagation law.
In the step 4, a reactive power measurement value of the line to be detected is obtained, the reactive power loss of the line to be detected is calculated, the difference value between the reactive power measurement value and the theoretical value of the reactive power loss in the step 1 is calculated, then, the difference value is compared with the reasonable deviation amount of the reactive power loss in the step 3, and the reactive power abnormal detection condition of the line is output.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to derive other drawings without creative efforts.
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a pi-type equivalent model of a line;
FIG. 3 is a simulated line topology according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a detection result according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
The embodiments of the present invention will be further described in detail with reference to the accompanying drawings, and the specific analysis process is as follows:
FIG. 1 is a flow chart of the present invention, comprising the steps of:
step one, establishing a line reactive loss model which does not relate to a phase angle, and determining a line reactive loss theoretical value;
fig. 2 is a pi-type equivalent model of a line, and based on the model, the reactive loss of the transmission line can be divided into two parts: capacitive reactive power of the equivalent parallel susceptance and inductive reactive power of the equivalent series reactance of the transmission line can be respectively expressed as:
Figure BDA0003615714340000021
the reactive loss of the transmission line can be expressed as
Figure BDA0003615714340000022
For the second term on the right side of equation (2), the expansion of the real part and the imaginary part can be simplified into
Figure BDA0003615714340000023
The square of its magnitude can be expressed as:
Figure BDA0003615714340000031
wherein, the third term on the right side of the equation is further analyzed to know
Figure BDA0003615714340000032
Thus, formula (2) can be written as
Figure BDA0003615714340000033
Similarly, for the n end:
Figure BDA0003615714340000034
in addition, the reactive power loss of the transmission line can be directly calculated by measuring the power at two ends, namely
Q L ＝Q m +Q n (8)
(6) + (7) in combination with (8), the reactive loss of the line can be rewritten as
Figure BDA0003615714340000035
As shown in (9), the reactive loss of the transmission line can be calculated by measuring the PMU/SCADA amplitude and the reference value of the parameter thereof, so that the theoretical value of the reactive loss of the line, that is, the theoretical value of the reactive loss of the line, can be calculated according to (9) by inputting the obtained PMU/SCADA measurement and the reference value of the transmission line (which can be obtained by an offline value or engineering experience), that is, by only inputting the obtained PMU/SCADA measurement and the reference value of the transmission line
Figure BDA0003615714340000036
Determining a PMU/SCADA positive sequence data error limit according to the precision grade of the line transformer; determining a line parameter deviation limit according to the actual operation condition of the line and the actual engineering requirement;
for PMU data, according to the accurate grade of voltage and current mutual inductor used by PMU device manufacturer and actual current place, the data error limit of voltage and current amplitude value measurement can be set
Figure BDA0003615714340000037
According to the actual operation condition of the transmission line and the accuracy required by reactive detection, the maximum deviation sigma of the resistance, reactance and susceptance off-line values from the actual operation values can be set R ,σ B ,σ X . In the embodiment of the present invention, setting
Figure BDA0003615714340000038
Thirdly, determining a reasonable reactive loss deviation amount under a set data error limit and a parameter deviation limit based on an error propagation law;
typically, we use the error in some unknown amount of direct observation as a measure of the accuracy of the observation. In practice, however, it is inconvenient or impossible to observe certain unknowns directly, and it is necessary to calculate them from direct observations of other observables through a defined functional relationship. Due to some objective factors, the independent observed values inevitably have errors, and therefore the function must also have errors. The error in the function and the error in the observed value necessarily have a certain relation, and from a statistical point of view, since the variable contains an error, the function is influenced by the error and also contains an error, and a law describing such a relation is called an error propagation law.
As described above, the error propagation law is a law describing a relationship between an error in an observed value function and an error in an observed value. In view of this, the reactive power loss for the transmission line can be expressed as a function of voltage, current amplitude and line parameters.
Q L (V m ,V n ,I m ,I n B, X) (12) is obtained by fully differentiating equation (12) and expressing it as a relative error:
Figure BDA0003615714340000041
taking into account the maximum error, the reactive loss limit deviation (i.e. threshold value)
Figure BDA0003615714340000042
) Expressed as:
Figure BDA0003615714340000043
wherein
Figure BDA0003615714340000044
σ B ,σ X And setting according to the step two. In addition, the partial derivatives result as follows:
Figure BDA0003615714340000045
substituting the equations (15) and (11) into the equation (14), the reasonable deviation amount of the reactive loss of the line (namely the reactive loss deviation threshold) considering the data measurement error and the line parameter deviation can be calculated.
Step four, calculating the deviation of each time section based on the real reactive loss measured value and the theoretical reactive loss value in the step 1, comparing the deviation with the reasonable reactive loss deviation amount of the line in the step 3, and outputting the abnormal condition of the line;
the reactive loss can be calculated by using a real reactive measured value of PMU/SCADA at two ends of the line, and can also be calculated by using an equation (8). When the PMU power factor angle has deviation or the SCADA data has time delay, a large error is generated in reactive measurement. Therefore, value Q 'of reactive loss measurement' m +Q′ n And the estimated value will deviate, i.e.
Q′ m +Q′ n -Q′ L (V′ m ,V′ n ,I′ m ,I′ n ,B,X)≠0 (16)
Wherein, V' m ,V′ n ,I′ m ,I′ n ,Q′ m ,Q′ n Respectively representing the voltage, the current and the reactive power measurement of the m end and the n end with deviation.
Considering that certain errors and deviations exist in phasor measurement and line parameters of PMU measured data, the following formula can be used for detecting reactive loss measurement abnormity.
Figure BDA0003615714340000046
Wherein the content of the first and second substances,
Figure BDA0003615714340000051
the maximum deviation amount of the reactive loss estimation value under the voltage, current amplitude error and line parameter deviation is considered, namely the reactive loss deviation threshold value.
FIG. 3 is a simulated circuit topology according to an embodiment of the present invention;
the example establishes a 500kV single-circuit transmission line (length 25.8km, resistance 0.3032 omega, reactance 6.7804 omega, susceptance 6.503 multiplied by 10) in PSCAD as shown in figure 4 -05 S), the PMU uploading period is 20 ms. The line working condition is set to (78.13-j10.53) MVA in a simulation mode, and 5min (15000 groups) steady-state measurement data can be obtained when a plurality of groups of different transmission powers are used by changing the load. The simulated PMU data includes the positive sequence voltage at two ends of the circuit, the amplitude and phase angle of the current and the measured power. Simultaneously, noise (the whole noise is normally distributed with the average value of 0, the standard deviation of the amplitude is 0.2 percent of each amplitude measurement, and the standard deviation of the phase angle is 0.1 degree) is added into the voltage and current data
In this example, three situations of line operation are set:
the method comprises the following steps of: the line parameters are set values, and meanwhile, no power factor angle deviation exists at two ends of the line.
Secondly, the line parameters are set values, and power factor angle deviations of 0.3 degrees and 0.3 degrees are added at the m end and the n end of the line respectively.
And thirdly, 2% positive deviation exists between the operating parameters of the line and the set values, and no power factor angle deviation exists at the two ends of the line.
As shown in figure 3 of the drawings,
in fig. 3, the deviation of the line reactive loss is within the threshold value and near 0, the line reactive loss is judged to be normal, and the situation is consistent with the simulation setting situation, thereby illustrating the effectiveness of the method.
In the second step of fig. 3, the reactive loss deviation exceeds the threshold, the reactive loss deviation of the line is judged, and the reactive loss deviation is consistent with the set simulation condition, so that the method can effectively detect the reactive loss abnormality of the line.
In fig. 3, the reactive loss deviation is within the threshold, and the data is determined to be normal, which shows that the method can effectively avoid the influence of the measurement error and the line parameter deviation on the reactive loss measurement anomaly detection.
Therefore, the embodiment of the invention is effective to the method for detecting the reactive loss abnormality of the power transmission line.
In conclusion, the line reactive power abnormity detection method which does not relate to the phase angle is feasible and has engineering application value.
It is noted that those skilled in the art will recognize that embodiments of the present invention are not described in detail herein.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (5)

1. A line reactive power abnormity detection method without involving phase angles is characterized by comprising the following steps:
step 1: establishing a line reactive loss model which does not relate to a phase angle, and determining a line reactive loss theoretical value;
step 2: determining a PMU/SCADA positive sequence data error limit according to the precision grade of the line transformer; determining a line parameter deviation limit according to the actual operation condition of the line and the actual engineering requirement;
and step 3: determining a reasonable reactive loss deviation amount under a set data error limit and a parameter deviation limit based on an error propagation law;
and 4, step 4: and (3) calculating the deviation of each time section based on the real reactive loss measured value and the theoretical reactive loss value in the step (1), comparing the deviation with the reasonable reactive loss deviation amount of the line in the step (3), and outputting the abnormal condition of the line.
2. The method for detecting the reactive power abnormality of the line, which does not relate to the phase angle, according to the claim 1 is characterized in that: in the step 1, a pi-shaped equivalent model of the power transmission line is established, a line reactive loss expression not related to a phase angle is obtained through theoretical derivation, PMU/SCADA voltage and current amplitude measurement data and line parameter reference values of a line to be detected are obtained, and a line reactive loss theoretical value is obtained through calculation.
3. The method for detecting the reactive power abnormality of the line, which does not relate to the phase angle, according to the claim 1 is characterized in that: in the step 2, firstly, the precision grades of the measured voltage and the current transformer/high-precision alternating current sampling telemechanical terminal (RTU) are determined according to the obtained data types (PMU/SCADA), then, the data error limits of the measured PMU/SCADA positive sequence voltage and current are set according to the precision grades, and similarly, the deviation limits of the offline values of the circuits during operation deviating from the true values are set according to the actual operation conditions of the circuits and the actual engineering requirements.
4. The method for detecting the reactive power abnormality of the line, which does not relate to the phase angle, according to the claim 1 is characterized in that: and 3, obtaining the amplitude value measurement values of the voltage and the current of the line to be detected, combining the amplitude measurement data error set in the step and the line parameter deviation, and obtaining the reasonable reactive loss deviation amount of the line under the working condition based on the error propagation law.
5. The method for detecting the reactive power abnormality of the line without involving the phase angle according to claim 1, characterized in that: in the step 4, a reactive power measurement value of the line to be detected is obtained, the reactive power loss of the line to be detected is calculated, the difference value between the reactive power measurement value and the theoretical value of the reactive power loss in the step 1 is calculated, then, the difference value is compared with the reasonable deviation amount of the reactive power loss in the step 3, and the reactive power abnormal detection condition of the line is output.
CN202210443798.1A 2022-04-26 2022-04-26 Line reactive power abnormity detection method without phase angle Pending CN114865619A (en)

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