CN105891678B - The UHVDC Transmission Lines fault distinguishing method of impedance is measured based on frequency band - Google Patents
The UHVDC Transmission Lines fault distinguishing method of impedance is measured based on frequency band Download PDFInfo
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- CN105891678B CN105891678B CN201610227884.3A CN201610227884A CN105891678B CN 105891678 B CN105891678 B CN 105891678B CN 201610227884 A CN201610227884 A CN 201610227884A CN 105891678 B CN105891678 B CN 105891678B
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- frequency band
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- fault distinguishing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/40—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to ratio of voltage and current
-
- 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
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/44—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to the rate of change of electrical quantities
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/10—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to mechanical injury, e.g. rupture of line, breakage of earth connection
- H02H5/105—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to mechanical injury, e.g. rupture of line, breakage of earth connection responsive to deterioration or interruption of earth connection
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Measurement Of Resistance Or Impedance (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
A kind of UHVDC Transmission Lines fault distinguishing method measuring impedance based on frequency band, the voltage and current of DC line both sides is sampled first, obtain the voltage and electric current under special frequency band, it then calculates both sides frequency band and measures impedance and its Sudden Changing Rate, Sudden Changing Rate and the fault distinguishing threshold value of setting are relatively differentiated into line fault, the present invention uses the ratio between frequency band voltage and electric current, i.e. frequency band measures impedance as failure criterion, frequency band when troubles inside the sample space measures impedance and is determined by systematic parameter and topology, theoretically not by transient voltage, the influence of current amplitude, traditional transient state harmonic protection can be overcome easily to be influenced by transition resistance and Line Attenuation, to line impedance parameter, line length, the change of the parameters such as smoothing reactor is insensitive.
Description
Technical field
It is specifically a kind of that resistance is measured based on frequency band the present invention relates to a kind of technology in power system failure diagnostic field
Anti- UHVDC Transmission Lines fault distinguishing method.
Background technology
For extra high voltage direct current transmission line frequently as the interconnection of big area networking, DC line is generally longer, trans-regional wide,
It runs in the presence of a harsh environment, the probability to break down is higher, and the reliability of fault distinguishing is low.
Currently, HVDC transmission line main protection configuration has traveling-wave protection and differential under-voltage protection, wherein differential is under-voltage
Protection also serves as the back-up protection of traveling-wave protection.Back-up protection configures current differential protection, and part engineering is also equipped with low-voltage simultaneously
Protection.However traveling-wave protection and differential under-voltage protection there are anti-transition resistance abilities it is low, sensitivity is low the problems such as.Traditional electric current
Differential protection does not account for the influence of capacitance current, only simply failure criterion is used as using the sum of both ends electric current, to keep away
Exempt from malfunction due to the current fluctuation caused by external area error, current differential protection action delay is longer, it is difficult to after playing DC line
The effect of standby protection.
Fault distinguishing method based on transient is that a kind of AC compounent generated therebetween using fault transient carries out failure
Know method for distinguishing, however, long DC line is fairly obvious for the attenuation of transient, and transient state component is easily by transition resistance
Influence.
By the retrieval discovery to the prior art, Chinese patent literature CN102522733A, publication date is 2012 06
Disclosed a kind of single-end electrical quantity complete fibre guard method of identification HVDC transmission line area internal and external fault by the moon 27,
It realizes the differentiation of troubles inside the sample space, external area error using the amplitude of specific frequency components in single-end DC filter branches, mainly
One-terminal data complete fibre protection for DC power transmission line in electric system.But the amplitude of the specific frequency components of the technology is easy
It is influenced by fault resistance and DC line attenuation, when being applied to extra-high straight-flow system, for high resistive fault and line
The differentiation of road end fault will lose selectivity.
Invention content
The present invention is directed to deficiencies of the prior art, proposes a kind of extra-high voltage direct-current measuring impedance based on frequency band
Line fault method of discrimination.
The present invention is achieved by the following technical solutions：
The present invention first samples the voltage and current of DC line both sides, obtains voltage and electricity under special frequency band
Stream then calculates both sides frequency band and measures impedance and its Sudden Changing Rate, and Sudden Changing Rate and the fault distinguishing threshold value of setting are relatively sentenced
Other line fault.
The frequency band measures the ratio between voltage and electric current under the special frequency band that impedance is either side.
The frequency band measures impedanceWherein：ZTMAnd ZTNRespectively
Impedance is measured for DC line both sides frequency band, M, N are denoted as the rectification side and inverter side of DC line both sides, U respectivelyM
(k)、IM(k)、UN(k)、IN(k) it is respectively voltage, electric current under special frequency band, NT is time window sampling number NT=Fs*
T, T are time windows, and Fs is sample frequency.
The special frequency band ranging from 400~2000Hz.
The Sudden Changing Rate Δ Z of the rectification sideTM=ZTM-ZTM0, the Sudden Changing Rate Δ Z of inverter sideTN=ZTN-ZTN0, wherein：ZTM0
For rectification side normal operation when frequency band measure impedance, ZTN0For inverter side normal operation when frequency band measure impedance.
The Sudden Changing Rate Δ ZTM＜ ZMsetAnd Δ ZTN＜ ZNsetWhen, judge to break down in DC line, ZMsetAnd ZNset
The respectively fault distinguishing threshold value of rectification side and inverter side.
The fault distinguishing threshold value ZMset=-0.1ZTM0, ZNset=-0.1ZTN0。
Technique effect
Compared with prior art, the present invention is not easily susceptible to the interference of signal noise and power swing, calculates simply, reduces
Hardware cost is easy to Project Realization, the influence of transition resistance and Line Attenuation can be effectively overcome, not by transient voltage and electricity
Flowing amplitude influences.
Description of the drawings
Fig. 1 is extra-high voltage DC transmission system structural schematic diagram；
Fig. 2 is DC filter structural schematic diagram：
In figure：(a) it is 12/24 double-tuned filter；(b) it is 12/24/26 three-tuned filter；
Fig. 3 is the method flow schematic diagram of embodiment 1；
Fig. 4 is to measure the analogous diagram that impedance differentiates DC line fault according to frequency band：
In figure：(a) it is positive circuit two-sided measurement voltage pattern；(b) it is positive circuit two-sided measurement map of current；(c) it is just
Polar curve road both sides frequency band component of voltage figure；(d) it is positive circuit both sides band current component map；(e) it is the positive circuit calculated
Both sides frequency band measures change in the instantaneous impedance spirogram；
Fig. 5 is to measure the analogous diagram that impedance differentiates external area error according to frequency band：
In figure：(a) it is positive circuit two-sided measurement voltage pattern；(b) it is positive circuit two-sided measurement map of current；(c) it is just
Polar curve road both sides frequency band component of voltage figure；(d) it is positive circuit both sides band current component map；(e) it is the positive circuit calculated
Both sides frequency band measures change in the instantaneous impedance spirogram；
Fig. 6 is to measure the analogous diagram that impedance differentiates DC line high resistance earthing fault according to frequency band：
In figure：(a) it is positive circuit two-sided measurement voltage pattern；(b) it is positive circuit two-sided measurement map of current；(c) it is meter
The positive circuit both sides frequency band of calculation measures change in the instantaneous impedance spirogram；
Fig. 7 is to measure impedance according to frequency band to differentiate analogous diagram of the electrode line curb line through different transition resistance earth faults：
In figure：(a) the mutation spirogram of impedance is measured for positive circuit rectification side frequency band；(b) it is positive circuit inverter side frequency
Band measures impedance diagram.
Specific implementation mode
It elaborates below to the embodiment of the present invention, the present embodiment is carried out lower based on the technical solution of the present invention
Implement, gives detailed embodiment and specific operating process, but protection scope of the present invention is not limited to following implementation
Example.
Embodiment 1
As shown in Figure 1, M, N are respectively DC line both end voltage and the measurement point of electric current, A, B, C, D indicates direct current respectively
Position of failure point outside line areas, wherein A, B are located at the connecting line of transverter and smoothing reactor, C, D be located at rectification side with it is inverse
Become at the exchange change of current busbar of side, F indicates DC line fault point position.It is DC filter schematic diagram in dotted line frame in Fig. 1,
As shown in Fig. 2, for extra-high voltage DC transmission system, general 12/24 double-tuned filter and 12,/24,/36 3 that configures is adjusted
Humorous filter.
When the described DC transmission system failure, during fault transient, fault point can be considered transient state harmonic source.Transient state is humorous
Wave source is located at DC line fault point, and transient state harmonic current flows to circuit both sides by fault point, and DC filter adjusts it
Lower impedance operator is presented in band current near humorous point, then the ratio between the component of voltage of the frequency band and current component, i.e. frequency band
Impedance is measured, numerical value is relatively low；And when external area error, the transient state harmonic wave of circuit side flows to line port by circuit, and another
Side transient state harmonic current then flows to DC line by line port.Since higher resistance is presented to transient AC component in DC line
Anti-, therefore, the frequency band that DC line side calculates measures the frequency band measurement impedance value that impedance value is relatively low, and the other side calculates
It is relatively low.It can be seen that DC line internal fault external fault, the Sudden Changing Rate difference that the frequency band that both sides calculate measures impedance is apparent, accordingly
Failure criterion can be formed.
As shown in figure 3, specific fault distinguishing method includes the following steps：
1) voltage, the electric current of DC line both sides are sampled, digital band pass filter is carried out to voltage, the electric current after sampling
Wave, obtains voltage and electric current under special frequency band, which is 400~2000Hz.
2) voltage, the electric current under special frequency band are utilized, rectification side and the ratio between inverter side voltage and electric current are calculated, is i.e. frequency band is surveyed
Measure impedance.
The frequency band measures impedanceWherein：ZTMAnd ZTNPoint
Not Wei DC line both sides frequency bands measure impedance, M, N are denoted as the rectification side and inverter side of DC line both sides, U respectivelyM
(k)、IM(k)、UN(k)、IN(k) it is respectively voltage, electric current under special frequency band, NT is time window sampling number NT=Fs*
T, T are time windows, and Fs is sample frequency.
3) special frequency band for calculating DC line both sides measures the Sudden Changing Rate of impedance.
The Sudden Changing Rate Δ Z of the rectification sideTM=ZTM-ZTM0, the Sudden Changing Rate Δ Z of inverter sideTN=ZTN-ZTN0, wherein：ZTM0
For rectification side normal operation when frequency band measure impedance, ZTN0For inverter side normal operation when frequency band measure impedance.
4) Sudden Changing Rate for measuring the frequency band that DC line both sides calculate impedance carries out logic judgment.
The Δ ZTM＜ ZMsetAnd Δ ZTN＜ ZNsetWhen, then it is determined as DC line troubles inside the sample space；ΔZTM≥ZMsetOr
ΔZTN≥ZNset, then it is determined as DC line external area error or normal operating condition, in formula, ZMsetAnd ZNsetFor the failure of setting
Differentiate threshold value.
The fault distinguishing threshold value ZMset=-0.1ZTM0, ZNset=-0.1ZTN0。
In the present embodiment, simulating, verifying is carried out to the differentiation of system different location failure shown in FIG. 1.Due to extra-high straightening
Flowing transmission system positive and negative anodes circuit, there is symmetry, the differentiation for DC line fault to only give the emulation of positive circuit
Verification result.Simultaneously as the structure of converting plant and Inverter Station has symmetry, therefore only give outside converting plant exchange lateral areas
The simulation results of fault distinguishing, it is specific as shown in Figures 4 to 7, wherein：Fig. 4 to DC line anode circuit 2000km at
The differentiation of metallicity failure is verified；The differentiation of rectifier terminal exchange side three phase short circuit fault is verified outside the areas Tu5Dui；
Fig. 6 and Fig. 7 to DC line high resistive fault be at positive circuit 1000km the differentiation through 1000 Ω transition resistance earth faults into
Verification is gone.Band component when the fault distinguishing threshold value of fault distinguishing is all in accordance with system normal operation in each figure calculate and
.Frequency band when according to normal operation measures impedance computation and obtains ZTM0=198.3 Ω, ZTN0=194.5 Ω, therefore fault distinguishing
Threshold value is respectively set as ZMset=ZNset=-20 Ω.
According to the verification result of Fig. 4 to Fig. 7, it may indicate that fault distinguishing method provided by the invention can reliably differentiate directly
Flow Line area internal and external fault, is not influenced by DC line length.For the DC line of 2000km, anti-transition resistance energy
Power is up to 1000 Ω.
Failure criterion is calculated using frequency band electrical quantity, the electrical quantity for using single specific frequency point in conventional method can be overcome
Easily by the defect of the interference effects such as signal noise, power swing.Using the form calculus of 400~2000Hz band component virtual values
Frequency band measures impedance, need not accurately calculate the amplitude of band component and each frequency component phase, of less demanding to sample frequency,
Theoretically the sample frequency of 4kHz can meet calculating and require.Therefore, this method calculates simple, reduces hardware cost, is easy to
Project Realization.Impedance is measured using frequency band and carries out fault distinguishing, frequency band measures impedance, and to only have system inherent structure related, therefore,
This method is not influenced by transient voltage and current amplitude, can effectively overcome the influence of transition resistance and Line Attenuation.For
It remains to reliably differentiate through 1000 Ω transition resistance earth faults, this method among 2000km circuits.
Compared with prior art, this method is measured impedance and is sentenced as failure by the ratio between frequency band voltage and electric current, i.e. frequency band
Frequency band when according to, troubles inside the sample space measures impedance and determined by systematic parameter and topology, theoretically not by transient voltage, current amplitude
It influences, traditional transient state harmonic protection can be overcome easily to be influenced by transition resistance and Line Attenuation.It is long to line impedance parameter, circuit
The change of the parameters such as degree, smoothing reactor is insensitive.
Claims (6)
1. a kind of UHVDC Transmission Lines fault distinguishing method measuring impedance based on frequency band, which is characterized in that first to direct current
The voltage and current of circuit both sides is sampled, and voltage and electric current under special frequency band are obtained, and is then calculated both sides frequency band and is measured
Sudden Changing Rate and the fault distinguishing threshold value of setting are relatively differentiated line fault by impedance and its Sudden Changing Rate；
The frequency band measures the ratio between voltage and electric current under the special frequency band that impedance is either side.
2. the UHVDC Transmission Lines fault distinguishing method according to claim 1 for measuring impedance based on frequency band, feature
It is that the frequency band measures impedanceWherein：ZTMAnd ZTNIt is respectively straight
Flow Line both sides frequency band measures impedance, and M, N are denoted as the rectification side and inverter side of DC line both sides, U respectivelyM(k)、IM
(k)、UN(k)、IN(k) it is respectively voltage, electric current under special frequency band, NT is time window sampling number NT=Fs*T, when T is
Between window, Fs is sample frequency.
3. the UHVDC Transmission Lines fault distinguishing method according to claim 2 for measuring impedance based on frequency band, feature
It is the special frequency band ranging from 400~2000Hz.
4. the UHVDC Transmission Lines fault distinguishing method according to claim 2 for measuring impedance based on frequency band, feature
It is the Sudden Changing Rate Δ Z of the rectification sideTM=ZTM-ZTM0, the Sudden Changing Rate Δ Z of inverter sideTN=ZTN-ZTN0, wherein：ZTM0It is whole
Frequency band when flowing the normal operation of side measures impedance, ZTN0For inverter side normal operation when frequency band measure impedance.
5. the UHVDC Transmission Lines fault distinguishing method according to claim 4 for measuring impedance based on frequency band, feature
It is the Sudden Changing Rate Δ ZTM＜ ZMsetAnd Δ ZTN＜ ZNsetWhen, judge to break down in DC line, ZMsetAnd ZNsetRespectively
For the fault distinguishing threshold value of rectification side and inverter side.
6. the UHVDC Transmission Lines fault distinguishing method according to claim 5 for measuring impedance based on frequency band, feature
It is the fault distinguishing threshold value ZMset=-0.1ZTM0, ZNset=-0.1ZTN0。
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109946562A (en) * | 2017-12-20 | 2019-06-28 | 中国电力科学研究院有限公司 | A kind of electrical power distribution network fault location method and system |
| CN110927646B (en) * | 2019-11-05 | 2021-02-19 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Method for positioning abnormal fault of direct-current voltage measurement of high-voltage direct-current power transmission system |
| CN112269063B (en) * | 2020-10-13 | 2024-01-02 | 国网江苏省电力有限公司电力科学研究院 | Transition resistance measurement method and system based on direct-current power distribution network differential current |
| CN112986744B (en) * | 2021-04-26 | 2021-08-06 | 湖南大学 | Frequency fault tolerance detection method and system under transient fault condition of power system |
| US12027843B2 (en) | 2021-09-14 | 2024-07-02 | Ge Infrastructure Technology Llc | Systems and methods for high-speed falling conductor protection in electric transmission systems |
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| CN101697411A (en) * | 2009-10-29 | 2010-04-21 | 华南理工大学 | Method for protecting transient state energy of DC power transmission line |
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