CN102780212B - Single-phase grounding traveling-wave protection device for distribution line - Google Patents
Single-phase grounding traveling-wave protection device for distribution line Download PDFInfo
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- CN102780212B CN102780212B CN201210253747.9A CN201210253747A CN102780212B CN 102780212 B CN102780212 B CN 102780212B CN 201210253747 A CN201210253747 A CN 201210253747A CN 102780212 B CN102780212 B CN 102780212B
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Abstract
The invention provides a single-phase grounding traveling-wave protection device for a distribution line, which comprises at least one convertor inserted on a circuit substrate, a protector, a monitor and an outlet relay, wherein the convertor is used for traveling-wave signal input and power frequency signal input, and a zero-mode current traveling-wave signal, a zero-mode voltage traveling-wave signal, a power frequency current signal and a power frequency voltage signal can be obtained; the protector comprises a traveling-wave module and a power frequency module; the traveling-wave module can obtain a zero-mode current traveling wave and a zero-mode voltage traveling wave under the line frequency range of 0-100KHz; meanwhile, according to the polarity of the zero-mode current traveling wave and the zero-mode voltage traveling wave, a protection criterion is formed; the power frequency module can be used for obtaining three-phase current and zero-sequence voltage for protecting a traveling-wave module from erroneous judgement; meanwhile, the device is locked when interphase faults are caused; and the outlet relay can give a tripping signal or an alarm signal according to the requirement. According to the technical scheme disclosed by the invention, when a neutral point non-effective grounding system of the distribution line is subjected to single-phase grounding faults, the faults can be quickly and accurately detected, and reliable protection action can be performed.
Description
Technical field
The present invention relates to protecting electrical power system and control technology, concrete, relate to a kind of distribution line single-phase earthing traveling-wave protection device.
Background technology
After system with non effectively earth ed neutral distribution line generation single phase ground fault, can only form loop by direct-to-ground capacitance, fault current is very little.Overcurrent protection, distance protection etc. based on traditional power frequency quality cannot action message under this failure condition.Single-phase earthing traveling-wave protection, owing to not reacting fault steady-state process, is occurring after single phase ground fault, and the polar relationship of voltage traveling wave and current traveling wave is all reliably set up in any earth neutral system, therefore can become the effective means addressing this problem.The realization of protective device also becomes the key addressing this problem.
The development of traveling-wave protection device is paid close attention to by Chinese scholars always.As far back as eighties of last century seventies, the capable ripple high-frequency orientation protector of First (traveling-wave protection of RALDA type) is just succeeded in developing abroad.China introduces two cover RALDA type protections at the initial stage eighties from Sweden, and installs at the distant line of brocade and Pingwu line respectively.But in fact RALDA type protection sample rate is only 10KHz, cannot effectively obtain travelling wave signal, lacks signal is carried out to the mathematical measure of effectively processing simultaneously, final RALDA type protection ends in failure.The development of traveling-wave protection device is subsequently absorbed in low ebb.Because traveling-wave protection need to be obtained the capable ripple of high frequency after fault, therefore protective device need to have high-speed data and obtains function; Hardware circuit should have stronger interference free performance simultaneously.In addition, the in the situation that of high sampling rate, data volume is larger, and therefore also claimed apparatus has stronger digital signal processing function.Along with the development of modern technologies, comprehensive utilization high speed digital signal processor (DSP) and complex programmable logic element (CPLD) are generally considered realizes the effective means that travelling wave signal obtains and processes on hardware.
In addition; in order to solve the problem that traveling-wave protection reliability is low, device also needs to have that power frequency component obtains and processing capacity, while ensureing to be expert at ripple protection module generation error starting; give locking by power-frequency voltage, distinguish single phase ground fault and double earthfault by power current simultaneously.
Therefore; need a kind of single-phase earthing traveling-wave protection device that is applicable to distribution line; can travelling wave signal and power frequency component be obtained and be processed simultaneously,, there is other types fault or reliable locking during with bus All other routes fault in simultaneously action message in the time of circuit generation single phase ground fault.Cause thereby overcome system with non effectively earth ed neutral the defect that traditional protection device is insensitive or lost efficacy because single phase ground fault phenomenon is not obvious, improve sensitivity and the reliability of phase-to-ground fault detection.
Summary of the invention
The present invention is just based on the problems referred to above; a kind of distribution line one-phase ground protection device has been proposed; can travelling wave signal and power frequency component be obtained and be processed simultaneously; in the time of system with non effectively earth ed neutral generation single phase ground fault; can accurately and fast detect fault, and make the protection action of response.
In view of this, the present invention proposes a kind of distribution line single-phase earthing traveling-wave protection device, comprise at least one converter, protector, watch-dog and the exit relay that are inserted on a circuit substrate; The current signal from loop to be measured and voltage signal are converted to secondary side current signal and secondary side voltage signal by described converter; Wherein, described converter comprises travelling wave signal input and power frequency component input, can obtain zero mould current traveling wave signal, zero mode voltage travelling wave signal, power current signal and power-frequency voltage signal; Described protector is accepted the described secondary side current and the secondary side voltage signal that are converted to from described converter, and signal is processed, then carry out protection algorithm, and then judge whether described loop to be measured single phase ground fault occurs, if broken down, result is exported to described watch-dog and described exit relay; Described watch-dog is connected to described protector, shows and stores the fault message that described protector transmits, and shows and transmits to described protector the definite value that user sets, and detecting the running status of described protector; Described exit relay is connected to described protector, receives the result of determination of described traveling-wave protection device, determines whether to send trip signal or alarm command according to described result of determination.
In such scheme, preferably, described protector comprises row mode piece and power frequency module; Wherein, described row mode piece is for travelling wave signal is obtained and processed, and described power frequency module is for obtaining and process power frequency component.
In such scheme, preferably, described row mode piece comprises that row wave datum is obtained loop, row ripple starts loop and travelling wave signal treatment loop; Wherein said row wave datum is obtained loop can be with the sampling rate of 200KHz, the zero mode voltage row ripple that the zero mould current traveling wave that loop to be measured medium frequency scope is 0 ~ 100kHz described in Real-time Obtaining and frequency range are 0 ~ 100kHz; Described row wave datum is obtained loop and is obtained loop and comprise second order active low-pass filter module, multicircuit switch module, A/D modular converter and dual port RAM module; Wherein, the free transmission range of described second order active low-pass filter module is 0 ~ 100KHz, described secondary side current signal and secondary side voltage signal are carried out to filtering, and described secondary side current signal and described secondary side voltage signal comprise zero mould current traveling wave signal and zero mode voltage travelling wave signal; Described multicircuit switch module is connected to described second order active low-pass filter module, for exporting successively described zero mould current traveling wave signal and zero mode voltage travelling wave signal to described A/D modular converter; Described A/D modular converter is connected to described multicircuit switch module, described row wave simulation signal is carried out to A/D conversion, every road signal A/D switching rate is 200KHz, after A/D conversion, obtain the digital signal of zero mould current traveling wave signal and zero mode voltage travelling wave signal, and transformation result is transferred to dual port RAM module; Described dual port RAM module, there are two groups of data/address buss and two group address buses, for storing from the described zero mould current traveling wave signal of described A/D modular converter and the digital signal transformation result of zero mode voltage travelling wave signal, and read the digital signal transformation result of described zero mould current traveling wave signal and zero mode voltage travelling wave signal by travelling wave signal treatment loop; Described row ripple starts loop, comprises second order active bandpass filiter module and voltage comparison module; The free transmission range of described second order active bandpass filiter module is 500Hz ~ 3KHz, can obtain the component of 500Hz ~ 3KHz in zero mould current traveling wave signal as the signal for starting judgement; Described voltage comparison module is connected to described second order active low-pass filter module, reception is described for starting the signal of judgement from described second order active bandpass filiter module, and determine described for the signal amplitude that starts judgement whether higher than the first predetermined amplitude, during higher than described the first predetermined amplitude, send enabling signal to described travelling wave signal treatment loop for the signal amplitude that starts judgement described; Described travelling wave signal treatment loop, comprises data acquisition module, wavelet transformation module, fault distinguishing module and power frequency communication module; Therefore described data acquisition module receives the enabling signal from described voltage comparison module, and from described dual port RAM, reads the digital signal of zero mould current traveling wave signal and zero mode voltage travelling wave signal; Described wavelet transformation module, the described zero mould current traveling wave digital signal that described data acquisition module is obtained and zero mode voltage row ripple digital signal are carried out wavelet transformation, obtain the polarity of modulus maximum and the modulus maximum of wavelet transformation, and obtain the wave head polarity of zero mould current traveling wave and zero mode voltage row ripple according to the polarity of described modulus maximum; Described fault initiating discrimination module; the described zero mould current traveling wave that described wavelet transformation module is obtained and the wave head polarity of zero mode voltage row ripple compare, if polarity is identical, and protective device described in involution; if polarity is contrary, start described power frequency communication module.Described power frequency communication module, if receive the enabling signal of described fault initiating discrimination module, with power frequency module communication, starts described power frequency module.
In such scheme, preferably, described wavelet transformation decomposes described zero mould current traveling wave digital signal with following form:
Wherein, i (n) is described zero mould current traveling wave digital signal,
for the small echo Coefficients of Approximation of described zero mould current traveling wave digital signal i (n),
for the wavelet conversion coefficient of described zero mould current traveling wave digital signal i (n).
After described dyadic wavelet transform, described zero mode voltage row ripple decomposing digital signal is become to following form:
Wherein, u (n) is described voltage traveling wave digital signal,
for the small echo Coefficients of Approximation of described zero mode voltage row ripple digital signal u (n),
for the wavelet conversion coefficient of described zero mode voltage row ripple digital signal u (n).
Described dyadic wavelet transform adopts the derived function of three subcenter B-spline functions as wavelet function, wavelet coefficient Xu Lie ﹛ hk ﹜
k ∈ z， ﹛ gk ﹜
k ∈ zfor:
﹛h
k﹜
k∈z=（0.125，0.375，0.375，0.125）（k=-1，0，1，2），﹛g
k﹜
k∈z=（-2，2）（k=0，1）。
In such scheme, preferably, described wavelet modulus maxima is defined as: for any given positive number ε >0, when meeting | n-n
0| when < ε, to n ≠ n arbitrarily
0, have
set up,
for the wavelet modulus maxima of described zero mould current traveling wave, it is positive and negative is the wavelet modulus maxima polarity of described zero mould current traveling wave; For any given positive number ε > 0, when meeting | n-n
0| when < ε, to n ≠ n arbitrarily
0, have
set up,
for the wavelet modulus maxima of described zero mode voltage row ripple, it is positive and negative is the wavelet modulus maxima polarity of described zero mode voltage row ripple.
In such scheme, preferably, described power frequency module comprises power frequency data acquisition loop and power frequency component treatment loop; Wherein, described power frequency data acquisition loop comprises second order active low-pass filter module, multicircuit switch module and A/D modular converter; Wherein, described second order active low-pass filter module cut-off frequency is 1.2KHz, and described secondary side voltage signal is carried out to filtering, and described secondary side voltage signal comprises three-phase current signal and residual voltage signal; Described multicircuit switch module, is connected to described second order active low-pass filter module, for described three-phase current signal and residual voltage signal are transferred to A/D modular converter successively; Described A/D modular converter is connected to described multicircuit switch module, described three-phase current signal and residual voltage signal are carried out to A/D conversion, obtain three-phase current digital signal and residual voltage digital signal, every road A/D switching rate is 2.4KHz, and transformation result is transferred to described power frequency component treatment loop; Described power frequency component treatment loop comprises that Fourier transform module, residual voltage determination module, phase current determination module and signal output module; Wherein, three-phase current digital signal and residual voltage digital signal are carried out Fourier transform by described Fourier transform module, obtains three-phase current amplitude and residual voltage amplitude; Described residual voltage determination module compares described residual voltage amplitude and the first predetermined amplitude, if described residual voltage amplitude is greater than described the first predetermined amplitude, starts phase current determination module, otherwise protective device involution; Described phase current determination module compares described three-phase current amplitude and the second predetermined amplitude, if described three-phase current amplitude is all less than described the second predetermined amplitude, enabling signal is outputed module, otherwise protective device involution; Described signal is outputed module and is set according to user, can provide trip signal or alarm signal, and signal is transferred to described exit relay.
Brief description of the drawings
Fig. 1 shows the block diagram of distribution line single-phase earthing traveling-wave protection device according to an embodiment of the invention;
Fig. 2 shows the hardware structure diagram of protection module according to an embodiment of the invention;
Fig. 3 shows protection module software flow pattern according to an embodiment of the invention.
Embodiment
In order more clearly to understand above-mentioned purpose of the present invention, feature and advantage, below in conjunction with the drawings and specific embodiments, the present invention is further described in detail.
Set forth in the following description a lot of details so that fully understand the present invention, still, the present invention can also adopt other to be different from other modes described here and implement, and therefore, the present invention is not limited to following public specific embodiment.
Fig. 1 shows the block diagram of distribution line single-phase earthing traveling-wave protection device according to an embodiment of the invention.
As shown in Figure 1, distribution line single-phase earthing traveling-wave protection device according to the present invention comprises at least one converter, protector, watch-dog and the exit relay that are inserted on a circuit substrate; The current signal from loop to be measured and voltage signal are converted to secondary side current signal and secondary side voltage signal by described converter; Wherein, described converter comprises travelling wave signal input and power frequency component input, can obtain zero mould current traveling wave signal, zero mode voltage travelling wave signal, power current signal and power-frequency voltage signal; Described protector is accepted the described secondary side current and the secondary side voltage signal that are converted to from described converter, and signal is processed, then carry out protection algorithm, and then judge whether described loop to be measured single phase ground fault occurs, if broken down, result is exported to described watch-dog and described exit relay; Described watch-dog is connected to described protector, shows and stores the fault message that described protector transmits, and shows and transmits to described protector the definite value that user sets, and detecting the running status of described protector; Described exit relay is connected to described protector, receives the result of determination of described traveling-wave protection device, determines whether to send trip signal or alarm command according to described result of determination.
In such scheme, preferably, described protector comprises row mode piece and power frequency module; Wherein, described row mode piece is for travelling wave signal is obtained and processed, and described power frequency module is for obtaining and process power frequency component.
In such scheme, preferably, described row mode piece comprises that row wave datum is obtained loop, row ripple starts loop and travelling wave signal treatment loop; Wherein said row wave datum is obtained loop can be with the sampling rate of 200KHz, the zero mode voltage row ripple that the zero mould current traveling wave that loop to be measured medium frequency scope is 0 ~ 100kHz described in Real-time Obtaining and frequency range are 0 ~ 100kHz; Described row wave datum is obtained loop and is obtained loop and comprise second order active low-pass filter module, multicircuit switch module, A/D modular converter and dual port RAM module; Wherein, the free transmission range of described second order active low-pass filter module is 0 ~ 100KHz, described secondary side current signal and secondary side voltage signal are carried out to filtering, and described secondary side current signal and described secondary side voltage signal comprise zero mould current traveling wave signal and zero mode voltage travelling wave signal; Described multicircuit switch module is connected to described second order active low-pass filter module, for exporting successively described zero mould current traveling wave signal and zero mode voltage travelling wave signal to described A/D modular converter; Described A/D modular converter is connected to described multicircuit switch module, described row wave simulation signal is carried out to A/D conversion, every road signal A/D switching rate is 200KHz, after A/D conversion, obtain the digital signal of zero mould current traveling wave signal and zero mode voltage travelling wave signal, and transformation result is transferred to dual port RAM module; Described dual port RAM module, there are two groups of data/address buss and two group address buses, for storing from the described zero mould current traveling wave signal of described A/D modular converter and the digital signal transformation result of zero mode voltage travelling wave signal, and read the digital signal transformation result of described zero mould current traveling wave signal and zero mode voltage travelling wave signal by travelling wave signal treatment loop; Described row ripple starts loop, comprises second order active bandpass filiter module and voltage comparison module; The free transmission range of described second order active bandpass filiter module is 500Hz ~ 3KHz, can obtain the component of 500Hz ~ 3KHz in zero mould current traveling wave signal as the signal for starting judgement; Described voltage comparison module is connected to described second order active low-pass filter module, reception is described for starting the signal of judgement from described second order active bandpass filiter module, and determine described for the signal amplitude that starts judgement whether higher than the first predetermined amplitude, during higher than described the first predetermined amplitude, send enabling signal to described travelling wave signal treatment loop for the signal amplitude that starts judgement described; Described travelling wave signal treatment loop, comprises data acquisition module, wavelet transformation module, fault distinguishing module and power frequency communication module; Therefore described data acquisition module receives the enabling signal from described voltage comparison module, and from described dual port RAM, reads the digital signal of zero mould current traveling wave signal and zero mode voltage travelling wave signal; Described wavelet transformation module, the described zero mould current traveling wave digital signal that described data acquisition module is obtained and zero mode voltage row ripple digital signal are carried out wavelet transformation, obtain the polarity of modulus maximum and the modulus maximum of wavelet transformation, and obtain the wave head polarity of zero mould current traveling wave and zero mode voltage row ripple according to the polarity of described modulus maximum; Described fault initiating discrimination module; the described zero mould current traveling wave that described wavelet transformation module is obtained and the wave head polarity of zero mode voltage row ripple compare, if polarity is identical, and protective device described in involution; if polarity is contrary, start described power frequency communication module.Described power frequency communication module, if receive the enabling signal of described fault initiating discrimination module, with power frequency module communication, starts described power frequency module.
In such scheme, preferably, described power frequency module comprises power frequency data acquisition loop and power frequency component treatment loop; Wherein, described power frequency data acquisition loop comprises second order active low-pass filter module, multicircuit switch module and A/D modular converter; Wherein, described second order active low-pass filter module passband is 0 ~ 1.2KHz, and described secondary side voltage signal is carried out to filtering, and described secondary side voltage signal comprises three-phase current signal and residual voltage signal; Described multicircuit switch module, is connected to described second order active low-pass filter module, for described three-phase current signal and residual voltage signal are transferred to A/D modular converter successively; Described A/D modular converter is connected to described multicircuit switch module, described three-phase current signal and residual voltage signal are carried out to A/D conversion, obtain three-phase current digital signal and residual voltage digital signal, every road A/D switching rate is 2.4KHz, and transformation result is transferred to described power frequency component treatment loop; Described power frequency component treatment loop comprises that Fourier transform module, residual voltage determination module, phase current determination module and signal output module; Wherein, three-phase current digital signal and residual voltage digital signal are carried out Fourier transform by described Fourier transform module, obtains three-phase current amplitude and residual voltage amplitude; Described residual voltage determination module compares described residual voltage amplitude and the first predetermined amplitude, if described residual voltage amplitude is greater than described the first predetermined amplitude, starts phase current determination module, otherwise protective device involution; Described phase current determination module compares described three-phase current amplitude and the second predetermined amplitude, if described three-phase current amplitude is all less than described the second predetermined amplitude, enabling signal is outputed module, otherwise protective device involution; Described signal is outputed module and is set according to user, can provide trip signal or alarm signal, and signal is transferred to described exit relay.
Fig. 2 shows the hardware structure diagram of protection module according to an embodiment of the invention;
As shown in Figure 2; zero mould current traveling wave signal and zero mode voltage travelling wave signal enter after protector, first enter second order active low-pass filter module, and the cut-off frequency of this second order active low-pass filter module is 100kHz; major function is filtering High-frequency Interference, prevents frequency alias simultaneously.Multicircuit switch MAX4639 can realize the alternative high speed COMS bus exchange switch of zero mould current traveling wave signal and zero mode voltage travelling wave signal, export successively two-way analog signal to A/D modular converter, in A/D modular converter, adopt 1 AD9240 high speed A/D conversion switch to realize the high speed A/D conversion to analog signal, the data sampling rate of each road analog signal is reached to 200KHz.Dual port RAM IDT7028 is for storing 2 railway digital signals after A/D conversion conversion, and memory space is 128Kbyte.
In addition; zero mould current traveling wave signal is after second order active low-pass filter module; also enter second order active bandpass filiter module; the band passband rate of second order active bandpass filiter module is 500Hz ~ 3kHz; extract the signal of 500Hz ~ 3kHz in the capable ripple of current failure, as the enabling signal of traveling-wave protection hardware.After second order active bandpass filiter module, signal enters one and forms level comparison loop by operational amplifier, when the signal level of 500Hz ~ 3kHz in the capable ripple of the current failure after band pass filter exceedes after default hardware-initiated level, the capable ripple of hardware starts loop and sends enabling signal to CPLD EMP7128S, CPLD EMP7128S triggers high speed digital signal processor TMS320C6713 and interrupts, and starts to carry out row ripple criterion.
CPLD EMP7128S is the core control section that row wave datum is obtained loop; it realizes coordination control to multicircuit switch module, A/D modular converter and dual port RAM module and the decoding of address/data signal; and then realize analog signal is converted in digital signal storage and dual port RAM IDT7028 module, simultaneously CPLD EMP7128S starts to carry out row ripple criterion at the hardware-initiated rear triggering high speed digital signal processor TMS320C6713 of traveling-wave protection.
Row ripple criterion completes taking DSP TMS320C6713 as core; this is a high-speed digital signal process chip; 32 of data/address buss; can carry out floating-point operation; precision is high; chip internal has 8 arithmetic elements, per secondly carries out 1,600,000,000 instructions, can meet the requirement of ultrahigh speed traveling-wave protection to data processing speed and precision simultaneously.In the time that the row ripple criterion of the exception handles in DSP TMS320C6713 is met, DSP sends to processor MCF5282 by interrupt signal, carries out the processing of power frequency criterion.
Three-phase current analog signal enters after protector, first enters second order active low-pass filter module, and the cut-off frequency of this second order active low-pass filter module is 1.2KHz, and major function is filtering High-frequency Interference, prevents frequency alias simultaneously.In A/D modular converter, adopt 1 MAX125 mould/number conversion chip, built-in chip type high-speed analog switch, can realize the high speed A/D conversion to multichannel analog signals, is 2.4KHz to the data sampling rate of each road analog signal.Data after sampling are stored in the internal RAM of MCF5282.When MCF5282 receives after DSP interrupt signal, start to carry out power frequency criterion.In the time that power frequency criterion meets, MCF5282 control is outputed module and is provided outlet information, and operates exit relay action.
Fig. 3 shows protection module software flow pattern according to an embodiment of the invention.
As shown in Figure 3, receiving after row ripple enabling signal:
Directly obtain the zero mould current traveling wave in described loop to be measured, zero obtained mould current traveling wave carried out to dyadic wavelet transform, after dyadic wavelet transform, zero mould current traveling wave is resolved into following form:
Wherein,
for the small echo Coefficients of Approximation of current traveling wave,
it is the wavelet conversion coefficient of zero mould current traveling wave.Ask for current traveling wave wavelet modulus maxima according to wavelet conversion coefficient, modulus maximum is defined as: for any given positive number ε > 0, when meeting | n-n
0| when < ε, to n ≠ n arbitrarily
0, have
set up,
it is zero mould current traveling wave wavelet modulus maxima; Utilize the polarity of the positive negative indication zero mould current traveling wave of zero mould current traveling wave wavelet modulus maxima;
Directly obtain the zero mode voltage row ripple in described loop to be measured, zero obtained mode voltage row ripple carried out to dyadic wavelet transform, after dyadic wavelet transform, zero mode voltage row Wave Decomposition is become to following form:
Wherein,
be the small echo Coefficients of Approximation of zero mode voltage row ripple,
it is the wavelet conversion coefficient of zero mode voltage row ripple.Ask for zero mode voltage row ripple wavelet modulus maxima according to wavelet conversion coefficient, modulus maximum is defined as: for any given positive number ε > 0, when meeting | n-n
0| when < ε, to n ≠ n arbitrarily
0, have
set up,
it is zero mode voltage row ripple wavelet modulus maxima; Utilize the polarity of the positive negative indication voltage traveling wave of zero mode voltage row ripple wavelet modulus maxima.
In such scheme, dyadic wavelet transform adopts the derived function of three subcenter B-spline functions as wavelet function, wavelet coefficient Xu Lie ﹛ h
k﹜
k ∈ z， ﹛ g
k﹜
k ∈ zfor:
﹛h
k﹜
k∈z=（0.125，0.375，0.375，0.125）（k=-1，0，1，2），﹛g
k﹜
k∈z=（-2，2）（k=0，1）。
By positive and negative the comparing of zero mode voltage row ripple and zero mould current traveling wave wavelet modulus maxima, in both opposite polarity situations, starting protection power frequency module; Otherwise protection involution.
Meanwhile, directly obtain three-phase current and residual voltage power frequency component.In the situation that protection power frequency module starts, utilize Fourier transform to ask for three-phase current and residual voltage amplitude.Utilize residual voltage amplitude and the first described predetermined amplitude to compare, if residual voltage amplitude is greater than setting value, next step criterion is carried out in protection; Otherwise protection involution.Subsequently three-phase current amplitude and the second predetermined amplitude are compared, if three-phase current amplitude is all less than the second predetermined amplitude, be judged as single phase ground fault, enabling signal is outputed module, otherwise protective device described in involution.
More than be described with reference to the accompanying drawings technical scheme of the present invention; consider in correlation technique; the single phase ground fault phenomenon of system with non effectively earth ed neutral is not obvious; and cause traditional protection method insensitive or lost efficacy; traveling-wave protection reliability is lower, the present invention proposes a kind of distribution line single-phase earthing traveling-wave protection device, in the time of distribution line system with non effectively earth ed neutral generation single phase ground fault; can accurately and fast detect fault, and make action message.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (9)
1. a distribution line single-phase earthing traveling-wave protection device, is characterized in that, comprises at least one converter, protector, watch-dog and the exit relay that are arranged on circuit substrate;
The current signal from loop to be measured and voltage signal are converted to secondary side current signal and secondary side voltage signal by described converter;
Described protector is accepted described secondary side current signal and described secondary side voltage signal, then according to described secondary side current signal and described secondary side voltage signal, obtain wave head polarity and power current and the power-frequency voltage amplitude of zero mould current traveling wave and zero mode voltage row ripple, finally judge according to described wave head polarity and described amplitude whether institute's protection circuit single phase ground fault occurs, if generation single phase ground fault, transmits trip signal to described exit relay; If there is not single phase ground fault, distribution line one-phase ground protection device described in involution;
Described exit relay is connected to described protector, if receive described trip signal, sends trip signal or alarm command.
Described protector comprises row mode piece and power frequency module; Wherein,
Described row mode piece is for travelling wave signal is processed, and described power frequency module is for processing power frequency component;
Described power frequency module comprises power frequency data acquisition loop and power frequency component treatment loop, wherein,
Filtering is carried out to described power current signal and described power-frequency voltage signal in described power frequency data acquisition loop, transmission and A/D conversion; Described power current signal comprises three-phase current signal, and described power-frequency voltage signal comprises residual voltage signal;
Described power frequency component treatment loop is after described power frequency module protection starts; described three-phase current signal and residual voltage signal are carried out to Fourier transform; obtain residual voltage signal amplitude and three-phase current signal amplitude; and judge; if described residual voltage signal amplitude is greater than the first predetermined amplitude; and described three-phase current signal amplitude is all less than the second predetermined amplitude; provide trip signal or alarm signal; and signal is transferred to described exit relay, otherwise distribution line one-phase ground protection device described in involution.
2. distribution line single-phase earthing traveling-wave protection device according to claim 1; it is characterized in that, current signal and voltage signal input that described converter is treated on survey time road are changed, and obtain described secondary side current signal and described secondary side voltage signal; wherein
Described secondary side current signal comprises: zero mould current traveling wave signal, power current signal; Described secondary side voltage signal comprises: zero mode voltage travelling wave signal, power-frequency voltage signal.
3. distribution line single-phase earthing traveling-wave protection device according to claim 1, is characterized in that, also comprises:
Watch-dog, is connected to described protector, shows and store the fault message of described protector transmission, receives and shows user's operation information, and transmit described operation information to described protector, and monitor the running status of described protector.
4. distribution line single-phase earthing traveling-wave protection device according to claim 1, is characterized in that, described row mode piece comprises that row wave datum is obtained loop, row ripple starts loop and travelling wave signal treatment loop; Wherein,
Described row wave datum is obtained the zero mode voltage travelling wave signal that converter medium frequency scope is 0～100kHz described in the Real-time Obtaining of loop zero mould current traveling wave signal and frequency range are 0～100kHz; And described zero mould current traveling wave signal and described zero mode voltage travelling wave signal are carried out to filtering, transmission and A/D conversion;
Described startup loop, obtains the output signal in loop and extracts for starting the signal of judgement from described row wave datum according to predetermined band, and judge whether to send enabling signal according to the first predetermined amplitude;
Described travelling wave signal treatment loop, receive described enabling signal and described row wave datum obtained to the zero mode voltage travelling wave signal that zero mould current traveling wave signal that the described frequency range of the output in loop is 0～100kHz and frequency range are 0～100kHz and carry out wavelet transformation, to obtain the wave head polarity of zero mould current traveling wave and zero mode voltage row ripple, whether the wave head polarity that then judges described zero mould current traveling wave and described zero mode voltage row ripple is identical, if identical, distribution line one-phase ground protection device described in involution; If not identical, start power frequency module.
5. distribution line single-phase earthing traveling-wave protection device according to claim 4, is characterized in that, described row wave datum is obtained loop and specifically comprised: second order active low-pass filter module, multicircuit switch module, A/D modular converter and dual port RAM module; Wherein,
The free transmission range of described second order active low-pass filter module is 0～100kHz, described zero mould current traveling wave signal and described zero mode voltage travelling wave signal are carried out to filtering, and obtaining described frequency range is the zero mould current traveling wave signal of 0～100kHz and the zero mode voltage travelling wave signal that frequency range is 0～100kHz;
Described multicircuit switch module is connected to described second order active low-pass filter module, and the zero mode voltage travelling wave signal that is 0～100kHz for be 0～100kHz by described frequency range zero mould current traveling wave signal and frequency range transfers to described A/D modular converter successively;
Described A/D modular converter is connected to described multicircuit switch module, the zero mode voltage travelling wave signal that the zero mould current traveling wave signal that is 0～100kHz to described frequency range and frequency range are 0～100kHz carries out A/D conversion, obtaining described frequency range is the zero mould current traveling wave digital signal of 0～100kHz and the zero mode voltage row ripple digital signal that frequency range is 0～100kHz, then transformation result is transferred to dual port RAM module;
Described dual port RAM module has two groups of data/address buss and two group address buses, for storing the described transformation result from described A/D modular converter, and is read described transformation result by described travelling wave signal treatment loop.
6. distribution line single-phase earthing traveling-wave protection device according to claim 5, is characterized in that, described row ripple starts loop and specifically comprises: second order active bandpass filiter module and voltage comparison module, wherein,
Described second order active bandpass filiter module is connected to described second order active low-pass filter module, the component that extracts 500Hz～3kHz for the zero mould current traveling wave signal that is 0～100kHz from the frequency range of described second order active low-pass filter module output as described for starting the signal of judgement;
Described voltage comparison module reception is described for starting the signal of judgement from described second order active bandpass filiter module, and judgement described for the amplitude of signal that starts judgement whether higher than described the first predetermined amplitude, during higher than described the first predetermined amplitude, send enabling signal to described travelling wave signal treatment loop for the amplitude of signal that starts judgement described.
7. distribution line single-phase earthing traveling-wave protection device according to claim 6, is characterized in that, described travelling wave signal treatment loop specifically comprises: data acquisition module, wavelet transformation module, fault initiating discrimination module and power frequency communication module, wherein,
Described data acquisition module receives the described enabling signal that starts loop from described row ripple, and obtains loop from described row wave datum and read the zero mode voltage row ripple digital signal that zero mould current traveling wave digital signal that described frequency range is 0～100kHz and frequency range are 0～100kHz;
Described wavelet transformation module, the zero mode voltage row ripple digital signal that the zero mould current traveling wave digital signal that is 0～100kHz to described frequency range and frequency range are 0～100kHz is carried out wavelet transformation, obtain respectively the first modulus maximum of described zero mould current traveling wave and the polarity of the first modulus maximum and described 0 the second modulus maximum of mode voltage row ripple and the polarity of the second modulus maximum, then according to the polarity of the polarity of described the first modulus maximum and described the second modulus maximum, obtain the first wave head polarity of described zero mould current traveling wave and the second wave head polarity of described zero mode voltage row ripple,
Described fault initiating discrimination module, compares described the first wave head polarity and described the second wave head polarity, if described the first wave head polarity is identical with described the second wave head polarity, and distribution line one-phase ground protection device described in involution; If described the first wave head polarity is contrary with described the second wave head polarity, start described power frequency communication module;
Described power frequency communication module, if receive the enabling signal of described fault initiating discrimination module, with power frequency module communication, informs that described power frequency module protection starts.
8. distribution line single-phase earthing traveling-wave protection device according to claim 1, is characterized in that, described power frequency data acquisition loop specifically comprises: second order active low-pass filter module, and multicircuit switch module and A/D modular converter, wherein,
Described second order active low-pass filter module is carried out filtering to described three-phase current signal and residual voltage signal;
Described multicircuit switch module is connected to described second order active low-pass filter module, for described three-phase current signal and residual voltage signal are transferred to described A/D modular converter successively;
Described A/D modular converter is connected to described multicircuit switch module, described three-phase current signal and residual voltage signal are carried out to A/D conversion, obtain three-phase current digital signal and residual voltage digital signal, then transformation result is transferred to described power frequency component treatment loop.
9. distribution line single-phase earthing traveling-wave protection device according to claim 8, is characterized in that, described power frequency component treatment loop specifically comprises: Fourier transform module, residual voltage determination module, phase current determination module and signal are outputed module, wherein,
Described Fourier transform module is carried out Fourier transform to described three-phase current digital signal and described residual voltage digital signal, obtains three-phase current amplitude and residual voltage amplitude;
Described residual voltage determination module compares described residual voltage amplitude and described the first predetermined amplitude, if described residual voltage amplitude is greater than described the first predetermined amplitude, start order phase current determination module, otherwise distribution line one-phase ground protection device described in involution;
Described phase current determination module compares described three-phase current amplitude and described the second predetermined amplitude, if described three-phase current amplitude is all less than described the second predetermined amplitude, enabling signal is outputed module, otherwise distribution line one-phase ground protection device described in involution;
Described signal is outputed module and is set according to user, can provide trip signal or alarm signal, and signal is transferred to described exit relay.
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