CN100583590C - Integrated failure positioning protection system for transfer line - Google Patents

Abstract

The invention discloses a transmission line integration failure location protection system, which mainly comprises an interface communication unit, a communication optical fiber network, a central relay protection unit and a plurality of breakers. The interface communication unit comprises a plurality of measurement and execution units and communication optical fiber network parts connected with the units; wherein, the measurement and execution unit comprises a current transformer, an interface unit, a communication Ethernet as well as a network switch; the current transformer is connected with a protected transmission line; the input end of the interface unit is connected with an output end of a three-phase current, the output end of the interface unit is connected with the breaker, and the communication end of the interface unit is connected with the communication optical fiber network through the network switch; a plurality of relays is connected with the optical fiber through the network switch. Featuring simple in structure, easy to realize and insensitive to the failure type, transition resistor, failure initial angle and power supply configuration, the system has no relation with the specific structure of the transmission network, needs no communication channel, and can be applied in the high-voltage transmission line protection, thus being a high-speed and precision failure location protection scheme.

Description

Integrated failure positioning protection system for transfer line

Technical field

The invention belongs to field of power, relate to a kind of protective device of electric power system, particularly a kind of electric main road integrated failure positioning protection system for transfer.

Background technology

The sixties in last century, Rockefeller has proposed the centralized transforming plant protecting system based on centralized computer system.This notion meets the thought of whole integrated protection very much, and promptly protective device not merely monitors discrete component, and can monitor all elements of a certain zone.Yet because the restriction of the computer technology (comprising hardware and software) and the communication technology, this idea is not applied to reality.From then on, the extensive use of digital technology is promoting the development of Protection Technology rapidly.The eighties in last century, along with the application based on the distributed treatment platform of being devoted to discrete component protection of conventional method, microprocessor is introduced in the protecting electrical power system gradually.So far, limited integrated protection still can only exist with the form of backup protection, and develops into secondary function gradually.

In the later stage seventies in last century, along with the expansion of scale of power, the requirement of excising fault for the raising stability of a system is fast encouraging the resist technology of people's research based on non-power frequency amount, and then improves the response speed of relaying protection.This has just caused the development of so-called " ultrahigh speed protection ", and it utilizes the transient signal in the fault-signal, is a kind of route protection based on row ripple and composition principle of stacking.Yet, because the limitation of time digital signal treatment technology is not used widely based on the protective device of this protection philosophy.

The progress that develops into relay protection of power system of the eighties in last century and the nineties provides new method, especially based on the resist technology of adaptive guard and artificial intelligence technology, has improved the performance of relaying protection greatly.Yet these only are the improvement of traditional protection technologies, can not promote to protect the development of new principle.

In recent years, microprocessor and sensor technology all had further development.This just makes in the past unpractiaca, utilizes the resist technology of fault transient signal to be reconsidered, and has attracted very big research interest.Discover that the fault transient high-frequency signal can be detected and quantize, this development for new protection philosophy and technology provides may.A lot of people have carried out a large amount of research in the context of detection of high frequency transient signal, and existing suitable novel protected technology is suggested, and have all proposed corresponding measurement and Digital Signal Processing.

Meanwhile, the marked improvement of relaying protection bracket signal disposal ability and the development of Communication Technique that adapts with it provide opportunity for examining the integrated protection notion again closely.Studies show that and can use new protection philosophy and the scheme of information design that is obtained by some transformer stations and element, they will be much better than existing resist technology based on single power station or element.At this on the one hand, the new resist technology of having invented based on the transient state amount has not only been inherited the ability of protection single assembly, can also be used to being designed for new departure of electric power system integrated protection when modern communication technology is supported.

Summary of the invention

The objective of the invention is to propose a kind of novel electric main road integrated failure positioning protection system for transfer; this system is when transmission line breaks down; based on the capable ripple of the high frequency transient that exists in fault current signal transmission characteristic on the line and the reflection characteristic on discontinuity point; catch this signal by integrated fault location protection relay; write down the time of advent and the polarity of various travelling wave signals; relatively their time of advent and polarity just can be determined faulty section then, and can further provide abort situation information.

In order to realize above-mentioned task, the present invention takes following technical solution:

A kind of electric main road integrated failure positioning protection system for transfer, this system mainly comprises a plurality of circuit breakers that are connected on Networks of Fiber Communications, a plurality of interface communications unit, a plurality of integrated relay protections unit and the transmission line, it is characterized in that:

Described a plurality of integrated relay protections unit is installed in all transformer stations of system, is independently monitoring the parameter of electric power system separately;

Described each interface communication unit comprises to be measured and control unit, and this interface communication unit is connected on the power equipment by various transducers;

Described measurement comprises current transformer, interface unit, communication Ethernet and the network switching that links to each other with protected power transmission line with control unit; its annexation is: current transformer; the input of interface unit links to each other with the three-phase current output of current transformer; the output of interface unit links to each other with circuit breaker; the communication terminal of interface unit links to each other with this telecommunication optical fiber network by network switching, and a plurality of integrated relay protections unit links to each other with this telecommunication optical fiber network by network switching.

Electric main of the present invention road integrated failure positioning protection system for transfer can be applied to the protection of high voltage transmission line; the concrete structure of this system and power distribution network is irrelevant; do not need channel; constitute simple; be easy to realize, and be insensitive to fault type, transition resistance; fault initial angle and power configuration are a kind of high speed and accurate fault location protection scheme.

Description of drawings

Fig. 1 is an electric main of the present invention road integrated failure positioning protection system for transfer structure chart;

Fig. 2 is configuration of multiterminal transmission line and Bewley-Lattice figure;

Fig. 3 is the integrated relay protection unit that connects by Ethernet;

Fig. 4 is the response of circuit P relaying protection unit when going up apart from S end bus 80km place generation a phase earth fault; Wherein, (a) primary fault electric current; (b) response of R end relaying protection unit, bus place; (c) response of S end relaying protection unit; (d) response of T end relaying protection unit;

Fig. 5 is the response that circuit P goes up relaying protection unit when bus R end 2km place breaks down; Wherein, (a) response of S end relaying protection unit, bus place; (b) response of R end relaying protection unit, bus place; (c) response of T end relaying protection unit, bus place;

The embodiment the present invention who provides below in conjunction with accompanying drawing and principle and inventor is described in further detail.

Embodiment

Referring to Fig. 1, Fig. 1 is an integrated failure positioning protection system for transfer line of the present invention, and it comprises interface unit, and fiber optic network is concentrated three parts of integrated protection relay unit, wherein:

Interface unit (IU) is a kind of measurement and control unit, and it is connected on the power equipment by various transducers.These transducers are traditional current transformer, traditional voltage transformer (CT ' s/VT ' s), optics combination sensor or electronics combination sensor.The analog and digital signal that measures is converted into light signal and delivers to the integrated relay protection unit by the fiber optic network of redundancy.Interface unit (IU) also receives and carries out the control signal of being sent by control loop.

Networks of Fiber Communications not only is connected with crucial interface unit and relaying protection unit, and other a large amount of equipment are also arranged, such as communication gate, and man-machine interface and gps clock etc.Use the communication protocol of standard can make the smart machine (IEDs) of different manufacturers manufacturing be easier to connecting system in the network.

The integrated relay protection unit comprises the general digital relay hardware platform of being made up of power supply, light signal input/output interface, protection microprocessor portion, and is solidificated in and exports the integrated fault location defence program that discrimination module, communication unit module are formed by program initialization module, fault detection module, fault location computing module, phase-model transformation module, multichannel filtration module, sequential logging modle, amplitude comparison module, counter, protection in this protection microprocessor.

The specific implementation of integrated relay protection unit is referring to Fig. 3.The current information of circuit P and circuit Q inserts the relaying protection unit by Ethernet, supposes that circuit P has fault, circuit Q fault-free, and fault detection module detects current anomaly, surpasses the limit value of adjusting, and starts the integrated relay protection unit this moment; The phase-model transformation module is carried out phase-model transformation to the faulty line magnitude of current, realizes the three-phase decoupling zero, and the line modulus after the use conversion extracts and the pairing value of fault high-frequency signal frequency band (40kHz-80kHz) by digital filtering method, is used for follow-up protection and calculates; Thereby sequential logging modle record row ripple due in calculates the needed time interval in the protection philosophy; judge the circuit internal fault external fault by anti-capable wave amplitude size; the decision-making module that trips at last carries out the analysis of nature of trouble, abort situation etc.; providing the tripping operation decision-making (is circuit P fault trip; circuit Q fault-free); decision information is fed back to Ethernet, transmit the information of whether tripping by Ethernet and give circuit.

The information that the relevant transformer station with other of measuring-signal that the reception of integrated relay protection unit is transmitted from the different places of this transformer station is transmitted by gateway determines whether break down in this transformer station or on the circuit that is attached thereto by calculating then.If the fault of detecting, it will send trip signal and disconnect relevant circuit breaker.

Come the scheme of proving institute proposition with a typical electric power networks as shown in Figure 2.Centralized fault location protection relay is installed in the transformer station, and is connected on the circuit by current transformer.Fault transient signal on the circuit is caught by this device, and the time of advent and the polarity of signal go on record, by relatively fault transient time of arrival (toa) and polarity just can be determined abort situation.This centralized integrated relay protection system can be applied to protect all transmission lines that are connected in this transformer station.The integrated relay protection unit extracts high-frequency signal from the fault transient state current signal, and by the modular transformation technology phase current signal is converted to corresponding line mould value.Signal mixed circuit converts three-phase current signal to mould 2 and mould 3 values exactly, realizes removing the function of pseudo-noise filter.The fixed-bandwidth signal of multichannel band pass filter from circuit extraction fault transient signal.The design frequency scope of integrated relay protection unit be 40kHz to 80kHz, therefore, the response speed of this scheme is not subjected to the influence of short circuit current level and power configuration.When sample frequency is 1MHz, the transmission speed of high frequency transient signal is during near the light velocity, and the certainty of measurement of this scheme can reach 150m.

Basic functional principle of the present invention and starting point are:

1) detection of abort situation

When breaking down on the power transmission line, the voltage and current signal with multiple frequency content is outwards propagated from the fault point by electrical lead.If these signals run on the transmission line discontinuity point and just have part signal and reflex to the fault point.The feature of these ripple signals is subjected to the influence of following Several Factors: abort situation, the characteristic impedance of failure path impedance and electrical lead.Transmission course with Bewley-Lattice figure expression as shown in Figure 2.

The integrated relay protection unit is installed in all transformer stations of system, is independently monitoring the parameter of electric power system separately.Among Fig. 2, protective relaying device is installed on the R of transformer station respectively, S and T.

The fault high-frequency signal frequency range that protective relaying device monitors is 40kHz～80kHz.Signal processing is exactly for determining high frequency fault-signal time of advent.In this band limits, bus is arranged by its capacitive composition mainly, and therefore, the high-frequency current signal of incident can be reversed and reflect back.Fault point in this band limits also can be with opposite polarity reflected current ripple.

Among Fig. 2, suppose that circuit P upward breaks down apart from the place of bus R end x distance, the broadband signal of its generation is propagated from the fault point to two side bus.When signal arrived bus, they will be reversed reflection.

The protective relaying device that is installed on bus S place among the figure at first detects from the fault point propagates the incident high-frequency signal of coming, and just detects the signal that reflects from far-end bus R then.Just polarity is opposite for signal that receives for the second time and the signal that receives for the first time.Therefore, these two kinds of signals have difference in essence.

The moment of utilizing the high frequency transient amount to arrive in succession in the protection algorithm is determined the faulty line in the network, and provides abort situation information.

The detected fault transient signal in A transformer station R place

The simplest situation approaches bus R place exactly and breaks down among Fig. 2 on circuit P.At this moment, the transient state amount that receives at first is Ir ₁, it is reflected back toward circuit subsequently, and can be reflected by the fault point again.Second transient state amount Ir ₂At time-delay tr ₂The back arrives; Tr ₂Be the time sum of transient signal from being reflected again and after bus being transferred to the fault point.This transmission time adopts following formula to calculate:

${\mathrm{<figure-callout\; id="2"\; label="tr"\; filenames="C2007100184100017H1.png"\; state="\{\{state\}\}">tr</figure-callout>}}_2=2\frac{x}{u}---\left(1\right)$

In the formula: u is the transmission speed of high-frequency signal on transmission pressure.

X shows that less than line length Lp fault betides protected circuit.

The detected fault transient signal in B transformer station S place

A) abort situation x＜Lp/2: the ripple signal that this moment, main consideration received at transformer station S place.It receives signal Is ₂Than initial row ripple Is ₁Arrive ts evening ₂Second.Is ₂With Is ₁Polarity is just opposite.

This moment time interval ts ₂With tr ₂Transmission path is identical, and its computing formula is provided by equation (1).

B) abort situation x＞Lp/2: this moment, bus S was more approached in the fault point.Suppose first fault transient signal Is ₁Transmission arrives S and holds ts consuming time ₁Second, wherein part signal is reflected back toward the fault point at once, has part signal once more again and is reflected at the place, fault point.The signal that is reflected by the fault point is at time interval ts ₂The back arrives the protective device of S end.This time interval just is that Transient High Frequency Signal is transferred to S end twice consuming time from the fault point, and therefore, its computing formula can be expressed as follows:

${\mathrm{<figure-callout\; id="2"\; label="ts"\; filenames="C2007100184100017H1.png"\; state="\{\{state\}\}">ts</figure-callout>}}_2=2\frac{\mathrm{Lp}-x}{u}---\left(2\right)$

Therefore, time difference of arriving of the detected Transient High Frequency Signal of protective device should equal that this signal is transferred to nearest bus end from the fault point and from time sum that the bus end reflects back.Although this time difference can be utilized,, then can obviously improve the performance of this scheme if can find from the signal of fault point reflection with from the difference of the signal of far-end bus reflection.

2) faulty section determines

Any bus end R that is installed in, the protective device at S and T place should be able to independently determine the faulty section of circuit.Adopting really herein, the technology of alignment road faulty section is based on the principle of identification from the transient state amount of bus end reflection.In a single day protective device detects first transient state amount row ripple and arrives, it just opening entry arrive time of the transient state travelling wave of bus end in succession.They correspond respectively to the high frequency transient signal from the fault point with from time of far-end bus reflected back.

The period of time T max that record keeps is corresponding to transient signal twice in propagation time on the nose road in system.If Lmax represents the length on nose road in the system, then should satisfy:

$T\max >2\frac{L\max }{u}$

If knowing the length of adjacent lines and the roughly transmission rate of Transient High Frequency Signal just can predict from the time of advent of adjacent lines far-end bus reflected signal.The time of advent one Fixed Time Interval is arranged from adjacent lines far-end bus reflected signal, this time interval is relevant with adjacent lines length, can be represented by the formula:

$t_{\mathrm{ref}1}-t_{\mathrm{first}}=2\frac{\mathrm{La}}{u}---\left(3\right)$

In the formula: La represents the length of adjacent lines.

By comparing the polarity of reflected traveling wave, the time of advent and amplitude just can be determined faulty section exactly.As seen from Figure 3, the reflected signal of the two ends bus of circuit P satisfies:

${\mathrm{<figure-callout\; id="4"\; label="t"\; filenames="C2007100184100017H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_4={\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="C2007100184100017H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+{\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="C2007100184100016H1.png,C2007100184100017H1.png"\; state="\{\{state\}\}">t</figure-callout>}}_3=2\frac{\mathrm{Lp}}{u}---\left(4\right)$

In the formula: t ₂* u/2 is corresponding to the distance of end from the fault point to R; t ₃* u/2 then is the distance that the S end is arrived in the fault point.

For the circuit Q that does not break down, at bus end S and T place detected reflection high frequency transient signal and transmission time t ₅Satisfy:

$L_q=t_5\frac{u}{2}---\left(5\right)$

A. determine faulty section from the protective relaying device of the R of transformer station

Be that example is illustrated this principle once more with Fig. 2.At the detected high frequency transient signal Ir R end first time ₁Come from the fault point, the transient signal that arrives in succession is respectively Ir subsequently ₂, Ir ₃And Ir ₄The time interval that these signals arrive the R bus all can be provided by equation (4).

The high frequency transient signal that reflects from bus T does not arrive the R end device in dominant record cycle t=2*Lq/u, can determine that thus fault occurs in circuit P rather than Q.

B. determine faulty section from the protective relaying device of the S of transformer station

, except the high frequency transient signal that detects the fault point and transmit, can also detect from R end and T and hold the signal that reflects at the protective relaying device at bus S place.As shown in Figure 2, the time interval of detected signal is all satisfied equation (4), not only can determine to have in the system line failure thus, can also determine that this fault occurs in circuit P.Transmission time ts ₄Corresponding to line length Lp.This can pass through comparison signal Is ₄And Is ₅The relative Amplitude value obtain confirming because they depend on line length and signal source.

C. determine faulty section from the protective relaying device of the T of transformer station

T hold a series of high frequency transient signals in detected front with hold at S detected identical, as shown in Figure 2.At this moment, can know just that from equation (4) system has line fault to take place, clearly its transmission time is corresponding to circuit P fault, and logicalnot circuit Q.Simultaneously, also can be from detected stronger travelling wave signal It ₅With signal It ₄There is identical polarity further to prove this conclusion.This point and S hold detected Is ₄And Is ₅Just opposite, because their polarity is opposite.

System responses is estimated:

As shown in Figure 2, transmission system wherein is a prototype with the vertical overhead transmission line of 400kV superhigh pressure of Britain's extensive use.Long respectively 128km of two sections transmission lines and 147km in this transmission system; At bus R, the short circuit current level at S and T place is respectively 5GVA, 35GVA and 20GVA.

Typical internal and external fault response:

The signal sampling frequency is 1MHz, and final result is got the signal of the 2 mould passages at Shf point place among Fig. 3.The sequential record cell of protective relaying device is output as the R of transformer station, the capable ripple of circuit P side among S and the T.

1) typical fault response

Figure 5 shows that the response when circuit P goes up apart from S end 80km place's generation a phase earth fault.Fig. 5 (a) is depicted as the initial value of three-phase current after the fault, and wherein the current amplitude of fault phase is apparently higher than non-fault phase.As seen from the figure, from fault mutually and non-fault mutually high frequency transient composition in the extraction fault current, fall into oblivion in the power frequency component that dominates.

Fig. 5 (b) is the response of R end protective relaying device, and signal is still taken from the Shf point among Fig. 4.Second high frequency transient component Ir ₂With the 3rd high frequency transient component Ir ₃The time interval that arrives bus R is respectively tr ₂And tr ₃Because second capable ripple Ir ₂With first row ripple Ir ₁Polarity identical, so can determine second capable ripple Ir ₂Be the fault point reflected wave.By time interval tr ₂And tr ₃Can determine to break down on the circuit P.

Fig. 5 (c) is the high frequency transient component at bus S place.By second capable ripple Is ₂With first row ripple Is ₁Polarity is Is as can be seen on the contrary ₂Reflected wave for the far-end bus; And the 3rd capable ripple Is ₃And Is ₁Polarity identical, so Is ₃Reflected wave for the fault point.The time interval by their arrival can be determined to break down on the circuit.The time interval ts of this moment ₂, ts ₃And ts ₄Just satisfy equation (4), can determine that thus fault occurs in circuit P.Simultaneously, signal Is ₄And Is ₅Also go on record.Because Is ₄Amplitude apparently higher than Is ₅, this further proves on the circuit P and breaks down.Therefore, device sends trip signal.

Fig. 5 (d) is the high frequency transient component at bus T place.As expected, they are extremely similar with Fig. 5 c.Different is, at time interval tt ₅There is very strong traveling-wave component It in the back ₅, and its polarity just with It ₁Identical.This proves that further fault occurs in circuit P, and therefore logicalnot circuit Q, need not to send trip signal.

2) different faults position response

For protective relaying device, it also should be able to have enough sensitivity response bus near terminal faults.Fig. 6 goes up response when bus R end 2km place breaks down for circuit P.Fig. 6 (a) is detected signal for S holds.Among the figure, the capable ripple and the initial row ripple that reflect from bus R end overlap each other together, therefore are difficult to analyze.

But, at ts ₃The reflected wave from the fault point that constantly receives is identical with initial polarity of traveling wave.Therefore, can be derived by equation (1) and draw in the position of fault point.Also there is the problem that overlaps each other in the response of bus R end, shown in Fig. 6 (b).But, hold the capable ripple of reflected back obviously corresponding to moment tr from bus S ₃, and its polarity is opposite with the polarity of initial row ripple, shows to determine abort situation by equation (2).

Fig. 6 (c) is the high frequency transient amount of T end.As expected, the signal received of its waveform and Fig. 6 (a) median generatrix S termination is identical.Different is, at tt ₅There is very strong signal It constantly ₅Because this signal has identical polarity with the initial row ripple, do not occur in circuit Q so can determine fault.

Under all failure conditions, this scheme all can be made correct response.

Claims (5)

1. electric main road integrated failure positioning protection system for transfer, this system mainly comprises a plurality of circuit breakers that are connected on Networks of Fiber Communications, a plurality of interface communications unit, a plurality of integrated relay protections unit and the transmission line, it is characterized in that:

Described a plurality of integrated relay protections unit is installed on respectively in each transformer station of system, is independently monitoring the parameter of electric power system separately;

Described interface communication unit comprises to be measured and control unit, and this interface communication unit is connected on the power equipment by various transducers;

Described measurement comprises current transformer, interface unit, communication Ethernet and the network switching that links to each other with protected power transmission line with control unit; its annexation is: the input of interface unit links to each other with the three-phase current output of current transformer; the output of interface unit links to each other with circuit breaker; the communication terminal of interface unit links to each other with this Networks of Fiber Communications by network switching, and a plurality of integrated relay protections unit links to each other with this Networks of Fiber Communications by network switching.

2. electric main as claimed in claim 1 road integrated failure positioning protection system for transfer is characterized in that, described various transducers are current transformer, voltage transformer, optics combination sensor or electronics combination sensor; Interface unit is accepted by control loop simultaneously and is sent the circuit breaker control signal.

3. electric main as claimed in claim 1 road integrated failure positioning protection system for transfer; it is characterized in that; described Networks of Fiber Communications is also connected to communication gate, man-machine dialog interface and gps clock, uses the network communication protocol of standard, and the intelligent electronic device of producing with different vendor connects.

4. electric main as claimed in claim 3 road integrated failure positioning protection system for transfer, it is characterized in that, described integrated relay protection unit receives from the current measurement information on each transmission line of transformer station by Networks of Fiber Communications, and by the information of communication gate acceptance from other relevant transformer stations, calculate immediately, whether have fault to take place to determine circuit coupled in this transformer station; Occur if detected fault, send instruction by Networks of Fiber Communications and remove the relevant circuit breaker of tripping.

5. electric main as claimed in claim 1 road integrated failure positioning protection system for transfer; it is characterized in that: said integrated relay protection unit comprises by power supply; the general digital relay hardware platform that light signal input/output interface and protection microprocessor portion are formed, and be solidificated in this protection microprocessor by the program initialization module; fault detection module; the fault location computing module; the phase-model transformation module; the multichannel filtration module; the sequential logging modle; the amplitude comparison module; counter; the integrated fault location defence program that protection outlet discrimination module and communication unit module are formed.

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