CN113030568B - Harmonic risk assessment method and device for direct-current power transmission system - Google Patents
Harmonic risk assessment method and device for direct-current power transmission system Download PDFInfo
- Publication number
- CN113030568B CN113030568B CN202110210545.5A CN202110210545A CN113030568B CN 113030568 B CN113030568 B CN 113030568B CN 202110210545 A CN202110210545 A CN 202110210545A CN 113030568 B CN113030568 B CN 113030568B
- Authority
- CN
- China
- Prior art keywords
- harmonic
- transmission control
- protection device
- power transmission
- harmonic voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/16—Spectrum analysis; Fourier analysis
Abstract
The application discloses a harmonic risk assessment method and device for a direct current transmission system, wherein the method comprises the following steps: harmonic voltage disturbances with a plurality of frequencies are input into the direct-current power transmission control protection device, and a harmonic amplitude response coefficient and a phase response coefficient corresponding to each harmonic voltage disturbance are calculated; obtaining harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, and recording corresponding frequency as harmonic risk frequency; harmonic voltage disturbance in a harmonic risk frequency range is simultaneously input into the direct current transmission control protection device, and protection actions and harmonic damping in different faults are tested; comparing the protection action with a preset protection action, and judging whether the direct current transmission control protection device has the conditions of operation rejection and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification. The method and the device can cover harmonic oscillation risks, harmonic overproof risks and influences of harmonics on protection, and can comprehensively evaluate influences of the harmonics on direct-current transmission.
Description
Technical Field
The application relates to the technical field of power transmission line risk assessment, in particular to a harmonic risk assessment method and device for a direct-current power transmission system.
Background
With the rapid development of power electronic technology, novel power electronic devices are applied to a power system on a large scale, the power electronic characteristics of the system are prominent, a large amount of harmonic waves enter a power grid and gradually present new characteristics of high frequency and wide frequency domain, and safety and stability problems such as damage of electrical equipment, reduction of power grid stability and the like can be caused.
The influence on the direct current transmission control protection device in the harmonic environment comprises the following three aspects:
(1) under the environment that harmonic exists in the power grid, a control link of the control protection device generates a series of responses to the harmonic, and finally outputs corresponding harmonic components to react on the power grid. Two aspects need to be considered, namely, forming an unstable closed loop to cause oscillation instability of certain frequencies and influence the safe and stable operation of the system, for example, when a converter of the flexible direct-current transmission system operates under a working condition, the converter of the flexible direct-current transmission system presents capacitive impedance and negative resistance, forms an oscillation circuit with other equipment to cause divergent current, and seriously influences the safe and stable operation of the flexible direct-current transmission system; on the other hand, the control system is sensitive to harmonic components of certain frequencies, so that output harmonics exceed the standard.
(2) Under the harmonic wave environment, the accuracy of a protection algorithm is influenced, so that the protection criterion is subjected to misoperation, and the protection system is subjected to misoperation.
(3) Under the harmonic wave environment, when corresponding faults occur, the harmonic wave components cause the failure of the protection criterion, and therefore the rejection of the protection system is caused.
The existing analysis and test method for the direct current transmission harmonic problem only aims at one of the three aspects, and the influence of the harmonic on the direct current transmission is difficult to evaluate comprehensively, so that the analysis of the direct current transmission harmonic problem is difficult to evaluate comprehensively and accurately.
Disclosure of Invention
The application provides a harmonic risk assessment method and device for a direct-current power transmission system, so that the harmonic oscillation risk, the harmonic overproof risk and the influence of harmonic on protection can be covered, and the influence of harmonic on direct-current power transmission can be comprehensively assessed.
In view of this, the present application provides, in a first aspect, a method for evaluating harmonic risk of a dc power transmission system, where the method includes:
inputting first harmonic voltage disturbances with multiple frequencies to a direct current power transmission control protection device, and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under the steady-state condition of the direct current power transmission control protection device;
obtaining the first harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, recording corresponding frequency as harmonic risk frequency, and recording the frequency range of the harmonic risk frequency;
simultaneously inputting second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct-current power transmission control protection device, testing the protection action of the direct-current power transmission control protection device when different faults occur in the direct-current power transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of each frequency;
comparing the protection action with a preset protection action, and judging whether the direct current transmission control protection device has the conditions of operation rejection and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification.
Optionally, the inputting first harmonic voltage disturbances with multiple frequencies to the dc transmission control protection device, and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under a steady-state condition of the dc transmission control protection device, includes:
s11: injecting the first harmonic voltage disturbance into the direct current power transmission control protection device;
s12: when the direct current transmission control protection device enters a steady state, calculating a harmonic amplitude response coefficient and a phase response coefficient of the direct current transmission control protection device;
s13: increasing the frequency value of the first harmonic voltage disturbance, and injecting the first harmonic voltage disturbance with increased frequency into the direct-current power transmission control protection device, wherein the increased frequency value is a preset value;
s14: repeating the steps S12-S13 until the frequency value of the first harmonic voltage disturbance after being promoted is larger than or equal to a cut-off frequency, and obtaining the harmonic amplitude response coefficient and the phase response coefficient corresponding to each first harmonic voltage disturbance.
Optionally, the calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance in a steady-state condition of the dc power transmission control protection device includes:
in the formula, VhRepresenting a first harmonic voltage disturbance, I, injected into said DC transmission control and protection devicehRepresenting harmonic current output by the direct current transmission control protection device in response; khmagRepresenting the amplitude response coefficient, KhangRepresenting a phase response coefficient; mag denotes taking amplitude and Ang denotes taking phase.
Optionally, the simultaneously inputting the second harmonic voltage disturbances of the multiple frequencies within the harmonic risk frequency range into the dc transmission control protection device, testing the protection actions of the dc transmission control protection device when different faults occur in the dc transmission system, and calculating the harmonic damping corresponding to the second harmonic voltage disturbances of each frequency, includes:
s21, simultaneously inputting the second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct current transmission control protection device;
s22, applying a fault N1 to the direct-current power transmission system, recording the protection action of the direct-current power transmission control protection device, and calculating the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
s23, after the direct current power transmission system recovers the initial state, applying the next fault to the direct current power transmission system, recording the protection action of the direct current power transmission control protection device, and calculating the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
s24: repeating step S23 until the corresponding protection actions and the harmonic damping for all preset faults are recorded.
Optionally, the second harmonic voltage disturbance of the plurality of frequencies is represented as:
in the formula, vhRepresenting a second harmonic voltage disturbance, f1-fnBelonging to the harmonic risk frequency, n representing the number of the second harmonic voltage disturbances; a is the disturbance amplitude of the second harmonic voltage, and A is smaller than or equal to a preset amplitude threshold value.
A second aspect of the present application provides a harmonic risk assessment apparatus for a dc power transmission system, the apparatus comprising:
the first calculation unit is used for inputting first harmonic voltage disturbances with multiple frequencies to the direct-current power transmission control protection device and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under the steady-state condition of the direct-current power transmission control protection device;
the harmonic risk frequency recording unit is used for obtaining the harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, recording corresponding frequency as harmonic risk frequency, and recording the frequency range of the harmonic risk frequency;
the testing unit is used for inputting second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct-current power transmission control protection device at the same time, testing the protection action of the direct-current power transmission control protection device when different faults occur in the direct-current power transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of each frequency;
the risk evaluation unit is used for comparing the protection action with a preset protection action and judging whether the direct current transmission control protection device has the conditions of operation refusal and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification.
Optionally, the first computing unit includes:
a first injection unit, configured to inject the first harmonic voltage disturbance into the dc power transmission control protection device;
the second calculation unit is used for calculating a harmonic amplitude response coefficient and a phase response coefficient of the direct-current power transmission control protection device when the direct-current power transmission control protection device enters a steady state;
the second injection unit is used for increasing the frequency value of the first harmonic voltage disturbance, and injecting the first harmonic voltage disturbance with increased frequency into the direct-current power transmission control protection device, wherein the increased frequency value is a preset value;
the first circulation unit is configured to repeat the steps of the second calculation unit and the second injection unit until the frequency value of the boosted first harmonic voltage disturbance is greater than or equal to a cut-off frequency, so as to obtain the harmonic amplitude response coefficient and the phase response coefficient corresponding to each first harmonic voltage disturbance.
Optionally, the calculating, by the first calculating unit, a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance in a steady-state condition of the dc power transmission control protection device includes:
in the formula, VhRepresenting a first harmonic voltage disturbance, I, injected into said DC transmission control and protection devicehRepresenting harmonic current output by the direct current transmission control protection device in response; khmagRepresenting the amplitude response coefficient, KhangRepresenting a phase response coefficient; mag denotes taking amplitude and Ang denotes taking phase.
Optionally, the test unit further includes:
a first input unit configured to simultaneously input the second harmonic voltage disturbances of a plurality of frequencies within the harmonic risk frequency range to the dc transmission control protection device;
a first fault applying unit configured to apply a fault N1 to a dc power transmission system, record a protection operation of the dc power transmission control protection device, and calculate the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
a second fault applying unit, configured to apply a next fault to the dc power transmission system after the dc power transmission system recovers the initial state, record a protection action of the dc power transmission control protection device, and calculate the harmonic damping corresponding to the second harmonic voltage disturbance of multiple frequencies;
and the second circulating unit is used for repeating the steps in the second fault applying unit until the corresponding protection actions and the harmonic damping of all preset faults are recorded.
Optionally, the second harmonic voltage disturbance of the plurality of frequencies is represented as:
in the formula, vhRepresenting a second harmonic voltage disturbance, f1-fnBelonging to the harmonic risk frequency, n representing the number of the second harmonic voltage disturbances; a is the disturbance amplitude of the second harmonic voltage, and A is smaller than or equal to a preset amplitude threshold value.
According to the technical scheme, the method has the following advantages:
the application provides a harmonic risk assessment method for a direct current transmission system, which comprises the following steps: inputting first harmonic voltage disturbances with a plurality of frequencies to the direct-current power transmission control protection device, and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under the steady-state condition of the direct-current power transmission control protection device; obtaining a first harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, recording corresponding frequency as harmonic risk frequency, and recording the frequency range of the harmonic risk frequency; simultaneously inputting second harmonic voltage disturbances of multiple frequencies within the harmonic risk frequency range into the direct-current power transmission control protection device, testing the protection action of the direct-current power transmission control protection device when different faults occur in the direct-current power transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of all the frequencies; comparing the protection action with a preset protection action, and judging whether the direct current transmission control protection device has the conditions of operation rejection and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification.
The harmonic risk frequency range is preliminarily screened by calculating the harmonic amplitude response coefficient, the phase response coefficient, the amplitude response coefficient and the phase response coefficient of the direct-current power transmission control protection device; carrying out a harmonic transient test according to the determined harmonic risk frequency range, observing whether the response action of the direct current transmission control protection device to be tested is correct or not, and determining whether the action rejection risk or the misoperation risk exists or not; meanwhile, harmonic damping of key electrical quantities such as voltage and current of the system is calculated, and whether a harmonic amplification effect exists is determined, so that harmonic oscillation risks, harmonic overproof risks and the influence of harmonic on protection can be detected, and the influence of harmonic on direct-current transmission can be comprehensively evaluated.
Drawings
Fig. 1 is a flowchart of a method of an embodiment of a method for harmonic risk assessment of a dc power transmission system according to the present application;
fig. 2 is a structural diagram of an apparatus according to another embodiment of the harmonic risk assessment apparatus for a dc power transmission system of the present application;
fig. 3 is a schematic flow chart of a harmonic steady-state test performed in an embodiment of the method for evaluating harmonic risk of a dc power transmission system according to the present application;
fig. 4 is a schematic diagram illustrating a test performed on a dc transmission control protection device according to an embodiment of the present application;
fig. 5 is a schematic flow chart illustrating a transient test performed on the dc power transmission control protection device according to the embodiment of the present application.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a flowchart of a method of an embodiment of a harmonic risk assessment method of a dc power transmission system according to the present application, as shown in fig. 1, where fig. 1 includes:
101. inputting first harmonic voltage disturbances with a plurality of frequencies to the direct-current power transmission control protection device, and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under the steady-state condition of the direct-current power transmission control protection device;
it should be noted that the direct current transmission control protection device is used for protecting the safe and stable operation of the direct current transmission system, and in order to avoid the influence of the harmonic environment on the direct current transmission control protection device, the harmonic risk frequency is primarily screened out in the application. Considering the response condition of the direct current transmission control protection device to different frequency harmonics and the sensitivity degree of the direct current transmission control protection device to the harmonics, the harmonic risk frequency can be preliminarily screened.
Firstly, when a harmonic steady-state test can be carried out on the direct current transmission control protection device, different initial frequencies, cut-off frequencies and preset values of boost frequencies can be selected according to different direct current transmission systems. For example, for a conventional direct-current power transmission system, because the control bandwidth and the control response speed of the direct-current power transmission control protection device are low, low-frequency harmonics can be generally considered, the frequency of first harmonic voltage disturbance can be selected to be 5-250 Hz, and the preset value of the boost frequency can be set to be 5 Hz; for the flexible direct current transmission system, because the control bandwidth and the control response speed are very high, high-frequency harmonic waves can be considered, the disturbance frequency of the first harmonic voltage can be selected to be 5-2500 Hz, and the preset value of the boost frequency can be selected to be 50 Hz. In the sensitive frequency range, the preset value of the boost frequency may be selected to be 1Hz, and it should be noted that the frequency range should avoid the frequency point of 50 Hz. In addition, in order to not influence the normal operation of the direct current transmission control protection device to be tested, the amplitude of the injected harmonic wave is not too large, meanwhile, in order to ensure the accurate calculation of the phase of the harmonic wave current and eliminate signal interference, the amplitude is not too small, and the typical amplitude value of the input first harmonic wave voltage disturbance is about 0.1% -0.5% of the steady state value. A specific flow diagram for performing the harmonic steady-state test is shown in fig. 3, which specifically includes:
s11: injecting first harmonic voltage disturbance into the direct current power transmission control protection device;
s12: when the direct-current power transmission control protection device enters a steady state, calculating a harmonic amplitude response coefficient and a phase response coefficient of the direct-current power transmission control protection device;
s13: increasing the frequency value of the first harmonic voltage disturbance, and injecting the first harmonic voltage disturbance after the frequency is increased into the direct-current power transmission control protection device, wherein the increased frequency value is a preset value;
s14: and repeating the steps S12-S13 until the frequency value of the first harmonic voltage disturbance after being promoted is larger than or equal to the cut-off frequency, and obtaining a harmonic amplitude response coefficient and a phase response coefficient corresponding to each first harmonic voltage disturbance.
It should be noted that the specific calculation formula of the harmonic amplitude response coefficient and the phase response coefficient corresponding to the first harmonic voltage disturbance is as follows:
in the formula, VhRepresenting a first harmonic voltage disturbance, I, injected into a DC transmission control and protection devicehRepresenting harmonic current output by the direct current transmission control protection device in response; khmagRepresenting the amplitude response coefficient, KhangRepresenting a phase response coefficient; mag denotes taking amplitude and Ang denotes taking phase. From the above equation, an amplitude profile and a phase profile can be obtained for the scanned frequency range.
102. Obtaining a first harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, recording corresponding frequency as harmonic risk frequency, and recording the frequency range of the harmonic risk frequency;
it should be noted that, if the calculated phase response coefficient belongs to a preset phase range, it indicates that the direct current to be measured may emit harmonic energy in the frequency range, and the smaller the amplitude response coefficient, the larger the emitted harmonic energy. Specifically, when the phase response coefficient corresponding to the first harmonic voltage disturbance is within a range of (90 ° or 180 °), and the amplitude response coefficient is smaller than a preset amplitude threshold (which may be an empirical threshold and obtained through experiments), the frequency value corresponding to the first harmonic voltage disturbance belongs to the harmonic risk frequency. Therefore, the obtained first harmonic voltage disturbance frequency values belonging to the harmonic risk frequencies can be counted to obtain the frequency range of the harmonic risk frequencies.
103. Simultaneously inputting second harmonic voltage disturbances of multiple frequencies within the harmonic risk frequency range into the direct-current power transmission control protection device, testing the protection action of the direct-current power transmission control protection device when different faults occur in the direct-current power transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of all the frequencies;
it should be noted that, second harmonic voltage disturbances of multiple frequencies within the harmonic risk frequency range may be simultaneously input into the dc transmission control protection device, and specifically, to avoid disturbance of the peak superposition effect between multiple harmonic sources to the steady-state operation of the dc transmission system, the phase selection may adopt the following expression:
in the formula, vhRepresenting a second harmonic voltage disturbance, f1-fnBelonging to harmonic risk frequency, wherein n represents the number of second harmonic voltage disturbances; a is the disturbance amplitude of the second harmonic voltage, and A is smaller than or equal to a preset amplitude threshold value.
The schematic diagram of testing the dc transmission control protection device by using the second harmonic voltage disturbance in the present application may be as shown in fig. 4, and the specific test flowchart thereof is as shown in fig. 5, including:
s21, simultaneously inputting second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct current power transmission control protection device;
s22, applying a fault N1 to the direct-current power transmission system, recording the protection action of the direct-current power transmission control protection device, and calculating harmonic damping corresponding to second harmonic voltage disturbance of a plurality of frequencies;
s23, after the DC power transmission system recovers the initial state, applying the next fault to the DC power transmission system, recording the protection action of the DC power transmission control protection device, and calculating the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
s24: step S23 is repeated until the corresponding protection actions and harmonic damping for all preset faults are recorded.
It should be noted that, in order to improve the test efficiency, a mode of harmonic simultaneous injection of multiple frequencies may be adopted, and the principle of harmonic set selection may be selected according to the frequency point of the phase response coefficient in the range of (90 °,180 °) obtained in the harmonic steady-state response test. And simultaneously inputting second harmonic voltage disturbances of multiple frequencies within the harmonic risk frequency range into the direct current transmission control protection device, respectively testing the direct current transmission control protection device for each fault in the direct current transmission system to obtain the protection action of the direct current transmission control protection device under each fault, and calculating the harmonic damping corresponding to the second harmonic voltage disturbances of the multiple frequencies. Specifically, the harmonic damping of each frequency can be obtained by prony analysis of key electrical quantities such as voltage and current and the like responded by the direct current transmission control protection device, and then the risk of the harmonic is judged by analysis of the protection action and the harmonic damping.
104. Comparing the protection action with a preset protection action, and judging whether the direct current transmission control protection device has the conditions of operation rejection and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification.
In the present application, the protection operation of the dc power transmission control protection device may be compared with an expected protection operation, so as to analyze whether there is a malfunction or a malfunction. By means of prony analysis of key electrical quantities such as voltage and current and the like responded by the direct current transmission control protection device, harmonic damping of each frequency can be obtained, and then harmonic characteristics are evaluated. If the damping is negative, there is a risk of harmonic amplification.
The harmonic risk frequency range is preliminarily screened by calculating the harmonic amplitude response coefficient, the phase response coefficient, the amplitude response coefficient and the phase response coefficient of the direct-current power transmission control protection device; carrying out a harmonic transient test according to the determined harmonic risk frequency range, observing whether the response action of the direct current transmission control protection device to be tested is correct or not, and determining whether the action rejection risk or the misoperation risk exists or not; meanwhile, harmonic damping of key electrical quantities such as voltage and current of the system is calculated, and whether a harmonic amplification effect exists is determined, so that harmonic oscillation risks, harmonic overproof risks and the influence of harmonic on protection can be detected, and the influence of harmonic on direct-current transmission can be comprehensively evaluated.
The present application further provides an embodiment of a harmonic risk assessment apparatus for a dc power transmission system, as shown in fig. 2, where fig. 2 includes:
a first calculating unit 201, configured to input first harmonic voltage disturbances with multiple frequencies to the dc power transmission control protection device, and calculate a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance in a steady-state condition of the dc power transmission control protection device;
the harmonic risk frequency recording unit 202 is configured to obtain a harmonic voltage disturbance in which a phase response coefficient belongs to a preset phase range and an amplitude response coefficient is smaller than a preset amplitude threshold, record a corresponding frequency as a harmonic risk frequency, and record a frequency range of the harmonic risk frequency;
the testing unit 203 is configured to input second harmonic voltage disturbances of multiple frequencies within the harmonic risk frequency range to the dc power transmission control protection device at the same time, test a protection action of the dc power transmission control protection device when different faults occur in the dc power transmission system, and calculate harmonic damping corresponding to the second harmonic voltage disturbances of each frequency;
a risk evaluation unit 204, configured to compare the protection action with a preset protection action, and determine whether the dc power transmission control protection device has a malfunction or a malfunction; if the harmonic damping is negative, there is a risk of harmonic amplification.
In a specific embodiment, the first computing unit 201 includes:
the first injection unit is used for injecting first harmonic voltage disturbance into the direct current transmission control protection device;
the second calculation unit is used for calculating a harmonic amplitude response coefficient and a phase response coefficient of the direct-current power transmission control protection device when the direct-current power transmission control protection device enters a steady state;
the second injection unit is used for increasing the frequency value of the first harmonic voltage disturbance, and injecting the first harmonic voltage disturbance after the frequency is increased into the direct-current power transmission control protection device, wherein the increased frequency value is a preset value;
and the first circulating unit is used for repeating the steps of the second calculating unit and the second injecting unit until the frequency value of the promoted first harmonic voltage disturbance is greater than or equal to the cut-off frequency, so as to obtain a harmonic amplitude response coefficient and a phase response coefficient corresponding to each first harmonic voltage disturbance.
The first calculation unit calculates a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under the steady-state condition of the direct-current power transmission control protection device, and the calculation unit comprises the following steps:
in the formula, VhRepresenting a first harmonic voltage disturbance, I, injected into a DC transmission control and protection devicehRepresenting harmonic current output by the direct current transmission control protection device in response; khmagRepresenting the amplitude response coefficient, KhangRepresenting a phase response coefficient; mag denotes taking amplitude and Ang denotes taking phase.
The test unit further includes:
the first input unit is used for simultaneously inputting second harmonic voltage disturbances of a plurality of frequencies in a harmonic risk frequency range into the direct-current power transmission control protection device;
a first fault applying unit configured to apply a fault N1 to the dc power transmission system, record a protection action of the dc power transmission control protection device, and calculate a harmonic damping corresponding to a second harmonic voltage disturbance of a plurality of frequencies;
the second fault applying unit is used for applying the next fault to the direct-current power transmission system after the direct-current power transmission system recovers the initial state, recording the protection action of the direct-current power transmission control protection device, and calculating the harmonic damping corresponding to the second harmonic voltage disturbance of the multiple frequencies;
and the second circulating unit is used for repeating the steps in the second fault applying unit until the corresponding protection action and harmonic damping of all preset faults are recorded.
The second harmonic voltage disturbance of the plurality of frequencies is represented as:
in the formula, vhRepresenting a second harmonic voltage disturbance, f1-fnBelonging to harmonic risk frequency, wherein n represents the number of second harmonic voltage disturbances; a is the disturbance amplitude of the second harmonic voltage, and A is smaller than or equal to a preset amplitude threshold value.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The terms "first," "second," "third," "fourth," and the like in the description of the present application and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that in the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" for describing an association relationship of associated objects, indicating that there may be three relationships, e.g., "a and/or B" may indicate: only A, only B and both A and B are present, wherein A and B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (8)
1. A harmonic risk assessment method for a direct current transmission system is characterized by comprising the following steps:
inputting first harmonic voltage disturbances with multiple frequencies to a direct current power transmission control protection device, and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance under the steady-state condition of the direct current power transmission control protection device, wherein the specific calculation formula is as follows:
in the formula, VhRepresenting a first harmonic voltage disturbance, I, injected into a DC transmission control and protection devicehRepresenting harmonic current output by the direct current transmission control protection device in response; khmagRepresenting the amplitude response coefficient, KhangRepresenting a phase response coefficient; mag represents taking amplitude, and Ang represents taking phase;
obtaining the first harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, recording corresponding frequency as harmonic risk frequency, and recording the frequency range of the harmonic risk frequency;
simultaneously inputting second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct-current power transmission control protection device, testing the protection action of the direct-current power transmission control protection device when different faults occur in the direct-current power transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of each frequency;
comparing the protection action with a preset protection action, and judging whether the direct current transmission control protection device has the conditions of operation rejection and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification.
2. The method according to claim 1, wherein the step of inputting first harmonic voltage disturbances of a plurality of frequencies to a dc transmission control protection device, and calculating a harmonic amplitude response coefficient and a phase response coefficient of each first harmonic voltage disturbance in a steady state condition of the dc transmission control protection device comprises:
s11: injecting the first harmonic voltage disturbance into the direct current power transmission control protection device;
s12: when the direct current transmission control protection device enters a steady state, calculating a harmonic amplitude response coefficient and a phase response coefficient of the direct current transmission control protection device;
s13: increasing the frequency value of the first harmonic voltage disturbance, and injecting the first harmonic voltage disturbance with increased frequency into the direct-current power transmission control protection device, wherein the increased frequency value is a preset value;
s14: repeating the steps S12-S13 until the frequency value of the first harmonic voltage disturbance after being promoted is larger than or equal to a cut-off frequency, and obtaining the harmonic amplitude response coefficient and the phase response coefficient corresponding to each first harmonic voltage disturbance.
3. The method according to claim 1, wherein the step of simultaneously inputting second harmonic voltage disturbances of a plurality of frequencies within the harmonic risk frequency range to the dc transmission control protection device, testing the protection actions of the dc transmission control protection device when different faults occur in the dc transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of each frequency comprises:
s21, simultaneously inputting the second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct current transmission control protection device;
s22, applying a fault N1 to the direct-current power transmission system, recording the protection action of the direct-current power transmission control protection device, and calculating the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
s23, after the direct current power transmission system recovers the initial state, applying the next fault to the direct current power transmission system, recording the protection action of the direct current power transmission control protection device, and calculating the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
s24: repeating step S23 until the corresponding protection actions and the harmonic damping for all preset faults are recorded.
4. The method according to claim 1, characterized in that the second harmonic voltage disturbances of the plurality of frequencies are represented as:
in the formula, vhRepresenting a second harmonic voltage disturbance, f1-fnBelonging to the harmonic risk frequency, n representing the number of the second harmonic voltage disturbances; a is the disturbance amplitude of the second harmonic voltage, and A is smaller than or equal to a preset amplitude threshold value.
5. A harmonic risk assessment device for a direct current transmission system, comprising:
the first calculation unit is configured to input first harmonic voltage disturbances of multiple frequencies to a direct current power transmission control protection device, and calculate a harmonic amplitude response coefficient and a phase response coefficient of each of the first harmonic voltage disturbances under a steady-state condition of the direct current power transmission control protection device, where a specific calculation formula is as follows:
in the formula, VhRepresenting a first harmonic voltage disturbance, I, injected into a DC transmission control and protection devicehRepresenting harmonic current output by the direct current transmission control protection device in response; khmagRepresenting the amplitude response coefficient, KhangRepresenting a phase response coefficient; mag represents taking amplitude, and Ang represents taking phase;
the harmonic risk frequency recording unit is used for obtaining the harmonic voltage disturbance of which the phase response coefficient belongs to a preset phase range and the amplitude response coefficient is smaller than a preset amplitude threshold, recording corresponding frequency as harmonic risk frequency, and recording the frequency range of the harmonic risk frequency;
the testing unit is used for inputting second harmonic voltage disturbances of a plurality of frequencies in the harmonic risk frequency range into the direct-current power transmission control protection device at the same time, testing the protection action of the direct-current power transmission control protection device when different faults occur in the direct-current power transmission system, and calculating harmonic damping corresponding to the second harmonic voltage disturbances of each frequency;
the risk evaluation unit is used for comparing the protection action with a preset protection action and judging whether the direct current transmission control protection device has the conditions of operation refusal and misoperation; if the harmonic damping is negative, there is a risk of harmonic amplification.
6. The harmonic risk assessment device of a direct current transmission system according to claim 5, characterized in that the first calculation unit comprises:
a first injection unit, configured to inject the first harmonic voltage disturbance into the dc power transmission control protection device;
the second calculation unit is used for calculating a harmonic amplitude response coefficient and a phase response coefficient of the direct-current power transmission control protection device when the direct-current power transmission control protection device enters a steady state;
the second injection unit is used for increasing the frequency value of the first harmonic voltage disturbance, and injecting the first harmonic voltage disturbance with increased frequency into the direct-current power transmission control protection device, wherein the increased frequency value is a preset value;
the first circulation unit is configured to repeat the steps of the second calculation unit and the second injection unit until the frequency value of the boosted first harmonic voltage disturbance is greater than or equal to a cut-off frequency, so as to obtain the harmonic amplitude response coefficient and the phase response coefficient corresponding to each first harmonic voltage disturbance.
7. The harmonic risk assessment device of claim 5, wherein the test unit further comprises:
a first input unit configured to simultaneously input the second harmonic voltage disturbances of a plurality of frequencies within the harmonic risk frequency range to the dc transmission control protection device;
a first fault applying unit configured to apply a fault N1 to a dc power transmission system, record a protection operation of the dc power transmission control protection device, and calculate the harmonic damping corresponding to the second harmonic voltage disturbance of a plurality of frequencies;
a second fault applying unit, configured to apply a next fault to the dc power transmission system after the dc power transmission system recovers the initial state, record a protection action of the dc power transmission control protection device, and calculate the harmonic damping corresponding to the second harmonic voltage disturbance of multiple frequencies;
and the second circulating unit is used for repeating the steps in the second fault applying unit until the corresponding protection actions and the harmonic damping of all preset faults are recorded.
8. The dc power transmission system harmonic risk assessment apparatus of claim 5, wherein the second harmonic voltage disturbances of the plurality of frequencies are represented as:
in the formula, vhRepresenting a second harmonic voltage disturbance, f1-fnBelonging to the harmonic risk frequency, n representing the number of the second harmonic voltage disturbances; a is the disturbance amplitude of the second harmonic voltage, and A is smaller than or equal to a preset amplitude threshold value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110210545.5A CN113030568B (en) | 2021-02-25 | 2021-02-25 | Harmonic risk assessment method and device for direct-current power transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110210545.5A CN113030568B (en) | 2021-02-25 | 2021-02-25 | Harmonic risk assessment method and device for direct-current power transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113030568A CN113030568A (en) | 2021-06-25 |
| CN113030568B true CN113030568B (en) | 2022-01-07 |
Family
ID=76461550
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110210545.5A Active CN113030568B (en) | 2021-02-25 | 2021-02-25 | Harmonic risk assessment method and device for direct-current power transmission system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113030568B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108599166A (en) * | 2018-05-29 | 2018-09-28 | 国网山东省电力公司聊城供电公司 | A kind of dynamic passive compensation harmonic suppression apparatus and control method |
| CN110927491A (en) * | 2019-12-03 | 2020-03-27 | 南方电网科学研究院有限责任公司 | Multi-harmonic source responsibility division method and device based on phase-free data |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3367412B2 (en) * | 1998-02-27 | 2003-01-14 | 日新電機株式会社 | Device to prevent isolated operation of distributed power supply |
| US8244406B2 (en) * | 2009-04-17 | 2012-08-14 | Howard University | System and method of monitoring and optimizing power quality in a network |
| CN202651788U (en) * | 2012-05-24 | 2013-01-02 | 中国海洋石油总公司 | Nonlinear load harmonic risk assessment system |
| CN103901273B (en) * | 2012-12-28 | 2017-12-22 | 白晓民 | Power grid harmonic wave detection method and Harmonic Measuring Equipment |
| CN107247185B (en) * | 2017-06-05 | 2019-09-06 | 西南交通大学 | Tractive power supply system harmonic impedance measurement device and its test method |
| CN109412189A (en) * | 2018-11-02 | 2019-03-01 | 国网重庆市电力公司电力科学研究院 | A kind of flexible HVDC transmission system DC side harmonics damping control method and system |
| CN109687462A (en) * | 2019-03-05 | 2019-04-26 | 国网重庆市电力公司电力科学研究院 | Soft lineal system high-frequency harmonic control method, system based on non-linear low-pass filter |
| CN110176762B (en) * | 2019-05-16 | 2022-08-09 | 国电南瑞科技股份有限公司 | Frequency domain impedance-based subsynchronous oscillation risk online evaluation method and device |
-
2021
- 2021-02-25 CN CN202110210545.5A patent/CN113030568B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108599166A (en) * | 2018-05-29 | 2018-09-28 | 国网山东省电力公司聊城供电公司 | A kind of dynamic passive compensation harmonic suppression apparatus and control method |
| CN110927491A (en) * | 2019-12-03 | 2020-03-27 | 南方电网科学研究院有限责任公司 | Multi-harmonic source responsibility division method and device based on phase-free data |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113030568A (en) | 2021-06-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Jamali et al. | A new fault location method for distribution networks using sparse measurements | |
| CN113219300B (en) | Power distribution network single-phase earth fault sensing method based on phase current transient state steady state | |
| Wang et al. | Data-driven diagnostics of mechanism and source of sustained oscillations | |
| Arefifar et al. | Online tracking of power system impedance parameters and field experiences | |
| Izadi et al. | Synchronous waveform measurements to locate transient events and incipient faults in power distribution networks | |
| Serfontein et al. | Continuous event-based harmonic impedance assessment using online measurements | |
| US11656263B2 (en) | Effective feature set-based high impedance fault detection | |
| Patel et al. | Energy-sorted Prony analysis for identification of dominant low frequency oscillations | |
| Afshar et al. | Analyzing performance of relays for high impedance fault (HIF) detection using hardware-in-the-loop (HIL) platform | |
| Khan et al. | An accurate algorithm of PMU-based wide area measurements for fault detection using positive-sequence voltage and unwrapped dynamic angles | |
| Paramo et al. | High-impedance non-linear fault detection via eigenvalue analysis with low pmu sampling rates | |
| CN113030568B (en) | Harmonic risk assessment method and device for direct-current power transmission system | |
| Zhu et al. | Injection amplitude guidance for impedance measurement in power systems | |
| Anshuman et al. | Enhanced visualization and characterization of low frequency oscillations in power system | |
| Hamzah et al. | Harmonic source location at the point of common coupling based on voltage magnitude | |
| Kannan et al. | A Novel Extended Noninvasive Harmonic Resonance Detection Technique for Public Low-Voltage Networks | |
| Bellan | Probability density function of three-phase ellipse parameters for the characterization of noisy voltage sags | |
| Obi et al. | An Extended ANN-Based High Speed Accurate Transmission Line Fault Location for Double Phase to-Earth Fault on Non-Direct-Ground | |
| Liu et al. | A new impedance-based approach for passive islanding detection scheme | |
| Artale et al. | DC series arc faults in PV systems. Detection methods and experimental characterization | |
| Krishna et al. | Detection of power system harmonics using NBPSO based optimally placed harmonic measurement analyser units | |
| Chatterjee et al. | Data-driven online detection of replay attacks on wide-area measurement systems | |
| Grasso et al. | Simulation Model and Experimental Setup for Power Quality Disturbances Methodologies Testing and Validation | |
| Shaik et al. | Combined classification of Power Quality Disturbances and Power System Faults | |
| Majumdar et al. | Assessment of Transient Disturbance using Discrete Fourier Transform and Feed Forward Neural Network based Hybrid Classifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |