CN106936136B - A kind of all-pass wave filtering harmonic elimination structure and control method for medium voltage network system - Google Patents

A kind of all-pass wave filtering harmonic elimination structure and control method for medium voltage network system Download PDF

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Publication number
CN106936136B
CN106936136B CN201710271988.9A CN201710271988A CN106936136B CN 106936136 B CN106936136 B CN 106936136B CN 201710271988 A CN201710271988 A CN 201710271988A CN 106936136 B CN106936136 B CN 106936136B
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ground connection
pass
earth
resistance
medium voltage
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CN106936136A (en
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李清远
吴疑
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Shaoguan Bai Rui Energy Saving Technology Co., Ltd.
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Shaoguan Bai Rui Energy Saving Technology Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

Abstract

Present invention offer is a kind of to be transformed into all-pass structure for medium voltage network system by grounding apparatus and the unit fusion of compensation functions of the equipments, the filtering harmonic elimination to low-frequency harmonics is wherein formed by the earth-return circuit of grounding apparatus, the filtering harmonic elimination to other harmonic waves is realized by improved capacitance reactive compensation equipment.Present invention also offers a kind of ground connection control method of the application structure.Compared to prior art, the present invention gets up the fusion of filtering compensation equipment, grounding apparatus, PT harmonic elimination apparatus and protective relaying device function, realizes and is grounded control and earthing wire-selecting trip avoidance function by relay protection system while full range filters harmonic elimination.

Description

A kind of all-pass wave filtering harmonic elimination structure and control method for medium voltage network system
Technical field
The present invention relates to electrical network field, particularly proposes a kind of transforming existing equipment as entirely for medium voltage network system The method that logical structure realizes full range filtering harmonic elimination, and a kind of ground connection control method is proposed accordingly.
Background technology
Pressure (10,35kV levels) neutral point of electric network be the earth-free method of operation in China, because not during generation singlephase earth fault Destruction system hree-phase symmetry and allow operation two hours.But when line mutual-ground capacitor electric current is more than 10A, earth point electric arc The grounding surge that automatic distinguishing is also easy to produce danger is unable to, has developed Neutral Point Through Low Resistance technology, humorous in recent years for this Shake compound grounding technology of ground connection and the fusion of resistance and automatic blowout coil etc..
With new energy expanding economy, wind-power electricity generation, the networking popularization of light generating, charging pile, which is registered one's residence, in addition causes There is new contradiction in power network, first, deteriorating with the power supply quality of power supply while benefit phenomenon easily occurred in user side, second, family Outer electric shock injures and deaths event increases, third, the equipment breakdown such as to burst increasingly multiple for overvoltage protection device.The reason for crossing benefit mainly can Control equipment generally using with PFC Semiconductor Converting Technology reactive power consumption decline, in addition load variations, mend device capability surely The reason such as more than needed causes；The reason for outdoor electric shock injury accident increases is mainly raw with expanding economy resident fishing, capital construction etc. Frequent activity living adds electric shock probability, in addition 10, the ground protection engineering reliability of 35kV level power networks it is also not high, get an electric shock and occur When easily cut regular link by mistake；The main reason for being burst as overvoltage protection device has ageing equipment, resonance overvoltage to cause its anti- The reasons such as pyrogenicity saturation are made in double action.
For the above situation, generally use filtering compensation technology, harmonic elimination technology and resonance grounding technology enter in the prior art Row solves, but above-mentioned technology still has following technological deficiency：
(1) the limitation and shortcoming of existing filtering compensation technology
Because active filter (APF) and solar energy, wind-powered electricity generation and frequency converter, SVG etc. all use Semiconductor Converting Technology, its core Operation element is all IGBT class speed-sensitive switches, thus Active Power Filter Technology can not eliminate it is high during IGBT class speed-sensitive switch normal works Harmonic pollution caused by frequency modulation carrier wave；Traditional capacitance filtering compensation device exist tuning point only to harmonic wave corresponding to tuning point and Left and right side frequency has filtering harmonic elimination effect, but the actual background harmonicses frequency spectrum of power network is abundant, in specific time section Continuous frequency spectrum is inside regarded as, and traditional capacitance filtering compensation device is often lost greatly, using the throwing of c-type high pass using second order high pass Money is big, thus compensation device generally reduces harm of the harmonic wave to electric capacity using string reactance, in addition as line capacitance electric current is more next Bigger, the filter capacity deficiency of traditional capacitance filtering compensation device is with compensating excessive contradiction.
(2) the limitation and shortcoming of existing harmonic elimination technology
10th, 35kV levels power network generally to tuning point and neighbouring harmonic and is disappeared using traditional capacitance filtering compensation device Humorous, useful effect frequency range is narrow, and because filtering compensation electric capacity isolated neutral (suspension) can not be ferromagnetic resonance, high-frequency resonant etc. Resonant energy provides leakage path over the ground；Other 10,35kV levels power network also uses PT harmonic elimination technologies, wherein bis- harmonic eliminations of PT extensively Check frequency be present to high frequency resonant signals in technology；Harmonic elimination technology of PT is then because the resonance potential of each frequency is reflected in PT once On winding three-phase star contact there is random change in time-harmonic wave magnitude of voltage size, and the operating valve value of non-linear element has frequency selection It is difficult.
(3) the limitation and shortcoming of existing grounding technology
The grounding technology that resonance grounding is widelyd popularize for current power network, but its loop inductance and the distribution over the ground of circuit change Multiple resonance points objectively be present in electric capacity, when easily causing tuning earth point Fundamental-frequency Current even if for zero also because harmonic current is excessive And the problem of being unable to blow-out；Earth point earth current detection difficult caused by diminishing after resonance compensation also be present；Other mesh Preceding centralized earthing wire-selecting control device accuracy also can not show a candle to protective relaying device with reliability, be filled if existing before ground connection occurs Put function difficulty review problem after disabler is difficult to prior confirmation and maintenance or changed.
Low resistance grounding is generally using the urban distribution network of cable to obtain certain application, but can reduce confession to a certain extent Electric reliability；Small resistor adds the compound earthing mode of automatic blowout coil to solve the technical problem that single mode is grounded, but The more complicated deficiency of the big control method of one-time investment be present.
The content of the invention
The shortcomings that it is an object of the invention to overcome prior art and deficiency, there is provided a kind of for medium voltage network system It transform existing equipment as method that all-pass structure realizes full range filtering harmonic elimination, and proposes a kind of ground connection control method accordingly.
The present invention is realized by following scheme：A kind of all-pass wave filtering harmonic elimination structure for medium voltage network system, it is special Sign is：Including low pass inductance LL, low-pass resistors RL, grounding resistance Re, asterism ground connection throwing back out close K, high pass electric capacity CH, high pass Resistance RH, basic-frequency branch inductance L1With basic-frequency branch electric capacity C1；
The low pass inductance LLOne end be used for simultaneously with the system power supply of medium voltage network and load connection, the other end is successively With low-pass resistors RL, grounding resistance RePass K is backed out with asterism ground connection throwing to connect；
The high pass electric capacity CHOne end be used for simultaneously with the system power supply of medium voltage network and load connection, the other end is successively With basic-frequency branch inductance L1With basic-frequency branch inductance capacitance C1Connection；The high pass electric capacity CHWith basic-frequency branch inductance L1Connection Point successively with the high pass resistance RH, grounding resistance RePass K is backed out with asterism ground connection throwing to connect.
As a further improvement on the present invention, the basic-frequency branch inductance L1Impedance and basic-frequency branch inductance capacitance C1's Capacitive reactance is identical, i.e. XL1=XC1；The high pass resistance RHThe controllable ground connection of three-phase star contact of extraction.
Compared to prior art, the present invention merges filtering compensation equipment, grounding apparatus, PT harmonic elimination apparatus three's functions Come, both played the compensation of capacitance reactive compensation device and filter function, and played earthing or grounding means grounding safety function again, moreover it is possible to be resonance Energy provides leakage path over the ground and realizes direct harmonic elimination at any time.
Present invention also offers a kind of ground connection control method realized for medium voltage network system by relay protection system, Applied to the above-mentioned all-pass wave filtering harmonic elimination structure for medium voltage network system, comprise the following steps：
S1：Carry out system is initially set, and puts into earthed switch K, and juxtaposition arc suppression coil output current is minimum；
S2：Signal acquisition is carried out, the signal includes：Voltage, electric current, frequency, switching value and instruction；
S3：Judge whether to meet that system earth, circuit zero-sequence current reach setting valve simultaneously；If so, then perform next step； If it is not, then return to step S1；
S4：Judge whether the ground connection quick-break circuit of setting, if performing step S5；If it is not, then simultaneously perform step S51 and S52；
S5：Ground path quick-break, return to step S1；
S51：Delay 0.1 second, then perform following steps simultaneously：
S511：Exit earthed switch K；
S512：Judge the whether super predetermined value of earth current harmonic content, perform S521 if not；
S52：Put into arc suppression coil and adjust the value to setting：Earth point Fundamental-frequency Current is minimum；And following walk is performed simultaneously Suddenly：
S521：Judge arc suppression coil load whether super predetermined value, if so, then by high pass resistance RHThree-phase star contact set It is set to suspended state；
S522：Search earth point, eliminate earth fault；
S523：Judge whether ground connection disappears, if so, then return to step S1；If it is not, then perform step S6；
S524：After delay 2 hours, step S6 is performed；
S6：Judge whether to meet that system earth and circuit zero-sequence current reach setting valve and reach delay time simultaneously, or Person receives artificial trip command, if performing step S7；
S7：Earthed circuit delay tripping, return again to step S1.
In order to more fully understand and implement, the invention will now be described in detail with reference to the accompanying drawings.
Brief description of the drawings
Fig. 1 is the schematic diagram of the all-pass wave filtering device for medium voltage network system of the present invention.
Fig. 2 is certain user 110KV stations electrical primary main wiring diagram
Fig. 3 is the system harmonic impedance schematic diagram of the present invention.
Fig. 4 is positive-negative sequence impedance structure figure.
Fig. 5 is zero sequence impedance structure chart.
Fig. 6 is the step flow chart of the control method for medium voltage network system of the present invention.
Fig. 7 is the ground relaying matching timing figure of the present invention.
Fig. 8 is the flow chart of the steady prosecutor method of distributed generation system off-grid of the present invention.
Fig. 9 is electrical primary main wiring diagram after the transformation of certain user 110KV stations.
Embodiment
With reference to embodiments and accompanying drawing the present invention is described in further detail, but embodiments of the present invention are unlimited In this.
In order to solve the defects of prior art, being total to filtering compensation device, earthing or grounding means and harmonic elimination apparatus of the invention Sexual function unit is merged to realize full range harmonic elimination, and accident treatment when earth fault occurs for system on this basis is based on relay Protection device provides a kind of method.Specific technical scheme and principle are described in detail by following examples.
Referring to Fig. 1, its schematic diagram for the all-pass wave filtering structure for medium voltage network system of the present invention.
The invention provides a kind of all-pass wave filtering structure for medium voltage network system, including low pass inductance LL, low pass electricity Hinder RL, grounding resistance Re, asterism ground connection throwing back out close K, high pass electric capacity CH, high pass resistance RL, basic-frequency branch inductance L1With fundamental frequency branch Road electric capacity C1；
The low pass inductance LLOne end be used for simultaneously with the system power supply of medium voltage network and load connection, the other end is successively With low-pass resistors RL, the ground connection throwing of grounding resistance Re and asterism backs out and closes K and connect；
The high pass electric capacity CHOne end be used for simultaneously with the system power supply of medium voltage network and load connection, the other end is successively With basic-frequency branch inductance L1With basic-frequency branch inductance capacitance C1Connection；The high pass electric capacity CHWith basic-frequency branch inductance L1Connection Point successively with the high pass resistance RH, the ground connection throwing of grounding resistance Re and asterism backs out and closes K and connect.
Wherein, the low pass inductance LL, low-pass resistors RL, grounding resistance Re and asterism ground connection throwing back out close K constitute low pass Impedance loop ZL。
The high pass electric capacity CH, basic-frequency branch inductance L1, basic-frequency branch inductance capacitance C1, high pass resistance RH, grounding resistance Re Backed out with asterism ground connection throwing and close K, constitute high pass impedance loop ZH。
And wherein, low pass loop impedance ZLWith high pass impedance loop ZHShare same earthed circuit, i.e. grounding resistance Re and Asterism ground connection throwing, which is backed out, closes K.
Further, the basic-frequency branch inductance L1Impedance and basic-frequency branch inductance capacitance C1Capacitive reactance it is identical, i.e. XL1= XC1。
The principle and effect of the all-pass wave filtering structure of the present invention are analyzed in detail below：
Firstth, X is worked asL1=XC1When CH、C1、L1、RHThe high-pass filtering loop of composition mainly absorb fundamental frequency above harmonic wave and it is humorous between Ripple, to the I of nth harmonic electric currentnAbsorbability is
The absorbability in the obvious higher loop of the harmonic wave frequency is stronger, and this point uses IGBT elements modulates carrier wave (one to suppression As 8 be less than 50kHz) harmonic wave effects caused by work are obvious.The nth harmonic voltage of bus is reduced to simultaneously
Nth harmonic decrease amount av is
By formula (1) (2) (3) it could be assumed that 1：Electric capacity CHInstalled capacity is bigger, resistance RHThe harmonic wave for being worth smaller device is inhaled Receipts ability is stronger, and the harmonic voltage on bus is lower.
Secondth, because high impedance is presented to low frequency subharmonic in high pass loop, low frequency subharmonic is then mainly by LL、RHComposition LPF loop absorbs.Work as RHEarth point ground connection when LL、RHForm Zero-pharse harmonic passage over the ground, no matter low pass inductance LLIt is Filter reactance or discharge coil, which are either grounded, becomes dual-purpose, and its value is much smaller than the primary side inductance value of voltage transformer, because And the resonant energy overwhelming majority of direct-to-ground capacitance is absorbed by low pass loop so as to protect voltage transformer (being commonly called as PT).
3rd, X is worked asL1=XC1When, device involved by invention is limited by formula (4) the harmonic voltage amplitude of n >=2
Bus subharmonic voltage magnitude is limited by formula (5), wherein ZLLFor low pass loop impedance, ImFor being somebody's turn to do for injected system Fractional harmoni electric current
ZL×Im(unit：V) formula (5)
Conclusion 2：Appropriate all-pass resistance value control bus harmonic voltage amplitude of choosing makes it always less than overvoltage protection device Minimum movements threshold value, overvoltage protection device is avoided to be burst because the out-of-limit perseveration of resonance overvoltage causes hot saturation.
4th, it is grounded accurate route selection quick tripping function
Judge that Earth Phase phase voltage reaches whole less than normal phase phase voltage, circuit out-of-balance current when passing through low resistance grounding Definite value, while Earth Phase phase current can accurately determine faulty line, then passage time Graded coordination reality more than normal phase phase current Switch now nearest from trouble point first trips, you can reaches the accurate route selection tripping operation purpose of ground connection.
Further improve, the parameter of all-pass wave filtering assembling structure is designed as follows in the present embodiment：
The present invention is by transforming former reactive power compensator as c-type high-pass structure and drawing three-phase high pass resistance star contact (Y Point), and former grounding apparatus (or discharge coil or special PT) composition all-pass structure, its parameter selection method is as follows
Basic demand：Realize C1、L1The basic-frequency branch FREQUENCY IMPEDANCE of composition is minimum, i.e. XC1=XL1；Effective compensation capacity is not Become.
1、CH、C1、L1Parameters design
If (a) reactance reuses, original compensation device installed capacity is Qq, series reactors are k%, if system nominal voltage For U, if high pass resistance Y points are ground capacity C1Operating voltage can be by bus line voltage UL(Y points are that controllable ground connection is then electric for selection Hold C1Operating voltage can be by bus phase voltage UL/ 1.73 choose), by
Obtain C1Installed capacity is QC1=Qq/K%(unit：kVar)
Such as C1Using Δ type connection, its installed capacity can reduce 3 times.
Because Fundamental-frequency Current is determined by inductance rated operational current, then the installed capacity Q of high-pass filtering compensating electric capacityCHFor
QCH=Qq(1-k%) formula (7)
Wherein, during the working earthing of high pass resistance Y points, when being grounded because of system there is displacement voltage, high-pass filtering electricity in Y points Hold CHOperating voltage type selecting need to consider by line voltage.
If (b) electric capacity reuses, former compensation device electric capacity installed capacity is Qq, series reactors k%, system nominal voltage UL, high pass resistance Y points are designed as being directly grounded, then
Filter capacitor CHOrder capacity QCEFor
Filter capacitor CHFundamental-frequency Current ICEFor
If CH、C1From same size, the capacitor of quantity, simply C1Using Δ type connection, then IL1=ICH, then by XL1= XC1Draw series reactance L1Inductance value be
2nd, high pass resistance RHParameter designing
If XC1-XL=0
(a) condition RH=XCH, RHThe value near the value
(b) because 10,35kV voltage total harmonic distortion factor limit values are respectively 4.0%, 3.0%, filter capacitor CHDesign Stream ability is 1.35ICH1, then RHValue will meet the harmonic current I absorbednLess than CH0.3 times of rated current, i.e.,
ByDraw
3rd, low pass loop parameter designing
Low pass loop is made up of low pass reactance with grounding resistance, and high and low logical loop resistance can share, due to low pass loop Purpose exempts from less than 3 times humorous ripples, fractional harmoni Resonance Harms, no matter selected primarily as low-frequency harmonics passage, protection PT Pick and place electric coil or ground connection becomes first winding and is used as low pass inductance, because its capacity is much larger than PT capacity thus can protecting PT, when It is greater than the PT used online by the use of 3 single-phase PT as its capacity during low pass inductance to damage to prevent its ferromagnetic resonance.
The application of the all-pass wave filtering structure of the medium voltage network system of the present invention, tool are introduced below by way of a specific example Body is as follows：
Fig. 2 and table 1 below are referred to, wherein Fig. 2 is certain user 110KV stations electrical primary main wiring diagram, and table 1 is actual measurement 10kVI sections dominate harmonic voltage harmonic ammeter (C phases).
The present embodiment 10kVI sections of table 1 dominate harmonic voltage harmonic ammeter (C phases)
(remarks：" ↑ " represents harmonic current and flows to system by load, and " ↓ " represents harmonic current and flow to load by system)
User's higher hamonic wave severe overweight can be analyzed by subordinate list 1, cause main transformer PT sleeve pipes as harmonic power transmission Capital equipment and demolish.Accident harmonic wave is exaggerated modulation carrier wave and formed from frequency converter modulation carrier wave, line mutual-ground capacitor Harmonic voltage source.
Solution：It is the compound ground connection that small resistor adds automatic blowout coil to change neutral point of main transformer earthing mode by the present invention Mode；A high pass filtering device is designed in frequency conversion load-side and realizes improvement with system composition full range harmonic elimination structure, sees Fig. 9, its For the electrical primary main wiring diagram after the transformation of certain user 110KV stations exemplified by I section.
Firstth, parameter designing is carried out
1st, please refer to Fig. 3, it is system harmonic impedance schematic diagram of the invention.
Ignore inductance, capacity cell internal resistance, using engineering approximate calculation, transformer neutral point presses earth-free mode, looks into Subordinate list 1 surveys data and 73 times, 85 subharmonic currents, voltage is substituted into formula
Obtain equation
XC1/85-85Z1=502.66/6.86
XC1/73-73Z1=548.41/5.72 solves system fundamental frequency induction reactance Z1=0.4068 (Ω) system capacitive reactance XC1=9167 (Ω)
According to<<IEEE 519-1992>>Defined current distortion limit value, the odd harmonic limit value of n >=35 is 50<ISC/IL< It is 0.7 when 100, even is 25%, the THD% 6 of odd.ISCFor the maximum short circuit current of points of common connection, ILFor public company 15~30min maximizing fundamental frequency load currents of contact.
It can be obtained by formula (3)
Again by ZH=RH+XCH, RH=XCHObtain RH=XCH=175 (Ω), PRH=(1060.2 × (26.17-6)/26.17)2/ (175000=3.8 kW)
CH=1/ (314XCH)=18.2 (uF)
QCH=3 × 6 × 6 × 1000/175=617 (kVar)
It is 11%, Q to take reactance RateC1=617 × 100/33=1870 (kVar)
2nd, combined resistance ground connection is changed to by system, its positive-negative sequence and zero sequence impedance structure as shown in Figure 4 and Figure 5, take ground connection Change fundamental frequency zero sequence impedance is 200 Ω into 10 Ω, the positive and negative sequence impedance of fundamental frequency, then by formula (1)
Obtain ZH=443.8 Ω
By formula (6)
Shown by above-mentioned calculating, do not consider power factor compensation, because earthing or grounding means Zero-pharse harmonic impedance is more earth-free small A lot, consider that earthing or grounding means has and overhaul actual condition out of service, by meeting that the earth-free method of operation time-harmonic wave of system administers Requirement, select filtering compensation electric capacity CH：Quantity 3, separate unit 209kVar/6kV, built-in electric discharge can be cancelled during parallel discharge coil Resistance.
High pass resistance RH：Between 103~443.8 Ω, 3 phase Y are connect single-phase resistance, and asterism is drawn, electrical power 5kW, temperature Rise and be less than 30 DEG C, stainless steel, cabinet top is installed.
Basic-frequency branch inductance L1Capacity：Quantity one, tri-phase iron core dry type, capacity 617kVar/ reactance Rates 11%, copper around Group.
Basic-frequency branch electric capacity C1Capacity：Compensating electric capacity 3, specification 623kVar/6kV, discharge resistance built in cancellation.
Please refer to Fig. 6, it is the step flow chart of the control method for medium voltage network system of the present invention.
, should present invention also offers a kind of ground connection control method based on relay protection system for medium voltage network system For the all-pass wave filtering harmonic elimination structure of above-mentioned medium voltage network system, following steps are specifically included：
S1：Carry out system is initially set, and puts into earthed switch K, and juxtaposition arc suppression coil output current is minimum；
S2：Signal acquisition is carried out, the signal includes：Voltage, electric current, frequency, switching value and instruction；
S3：Judge whether to meet that system earth, circuit zero-sequence current reach setting valve simultaneously；If so, then perform next step； If it is not, then return to step S1；
S4：Judge whether the ground connection quick-break circuit of setting, if performing step S5；If it is not, then simultaneously perform step S51 and S52；
S5：Ground path quick-break, return to step S1；
S51：Delay 0.1 second, then perform following steps simultaneously：
S511：Exit earthed switch K；
S512：Judge the whether super predetermined value of earth current harmonic content, perform S521 if not；
S52：Put into arc suppression coil and adjust to setting definite value：Earth point Fundamental-frequency Current is minimum；And following walk is performed simultaneously Suddenly：
S521：Judge arc suppression coil load whether super predetermined value, if so, then by high pass resistance RHThree-phase star contact (Y Point) it is arranged to suspended state；
S522：Search earth point, eliminate earth fault；
S523：Judge whether ground connection disappears, if so, then return to step S1；If it is not, then perform step S6；
S524：After delay 2 hours, step S6 is performed；
S6：Judge whether to meet that system earth and circuit zero-sequence current reach setting valve and reach delay time simultaneously, or Person receives artificial trip command, if performing step S7；
S7：Earthed circuit delay tripping, return again to step S1.
Illustrated below for the function in the control method of the system of the present invention：
1st, present invention design or modernization system neutral point are compound earthing mode, and preferred properties stabilization, reliability are high to break Road device is thrown and moves back earth point.Earthing or grounding means original state is resistance input, automatic blowout coil output current minimum；It is grounded and is Start-up study, calculates earthing capacitance current and (arc suppression coil response is slower using calculated value as desired value instruction regulation arc suppression coil Need presetting), after 0.1s exits grounding resistance, arc suppression coil starts to automatically adjust output, if now earth point current harmonic content High pass resistance Y points must be suspended more than preset value less than preset value and arc suppression coil load；If arc suppression coil automatically adjusted Failure does not disappear always in journey, but arc suppression coil works more than 2 hours, by code input grounding resistance delay classification excision failure Circuit is until earth fault disappears；System returns to original state after earth fault disappears.
2nd, route selection tripping operation, tool are grounded using the compound comparison method of voltage x current, load classification and time extreme difference matching method Body is：
2.1 use compound comparison method accurate judgement system earth failure
System occurs line voltage during single-phase earthing and keeps symmetrical, i.e. system A, B, C three-phase line voltages Uab、Ubc、UcaIt is equal, If the residual voltage U of PT open deltas0Reach setting valve, and PT once, secondary no broken string, when circuit is without phase shortage (broken string), after Electric protection system report：System earth.
2.2 phase voltage comparison methods determine Earth Phase
If earth fault has A, B two-phase phase voltage U when occurringa、UbMore than 0.577 times of line voltage three-phase average value, C phases Phase voltage Uc is less than 0.577 times of line voltage three-phase average value and then judges that C phases are grounded (other phases are similarly).
3rd, accurate route selection is realized using Neutral Point Through Low Resistance amplification zero sequence drying method
In order to ensure sensitivity, grounding resistance REDesign work electric current is generally higher than 2~3 times of system capacity current or more It is more.When single-phase earthing occurs for system, the loop that earth current does not flow through meets Ia+Ib+Ic=0, the loop that earth current flows through has Ia+Ib+Ic=I0, earth point current effective value I0=U0/(RE+r+Xc), wherein r is earth point equivalent resistance, XcHold for earth point It is anti-, detect I0The circuit that value reaches setting valve is the ground path selected.
4th, the method that tripping operation is grounded using load classification and time extreme difference matching method, it is specially：
4.1 load classification principles
By advance planning and decision-making, select safety preferential or power supply priority principle carries out load classification to all circuits：First, Quick-break class is grounded, person electric shock injury circuit easily occurs, or the ground connection such as big motor of cable, direct connection is permanent fault, Yi Fa Open up the circuit to be brought about great losses for short circuit accident；Must be kept when the 2nd, being grounded continuous power supply (such as wind farm grid-connected interconnection, Important security place etc.), transfer load or turn power successfully after ability ground tripping circuit；3rd, be grounded when resistance eutral grounding, Resonance grounding, it is earth-free all can circuit.
4.2 protective relaying device time differential fitting methods, please refer to Fig. 7, it is protected for the ground connection relay of the present invention Protect matching timing figure.
The qualified breaker open operation time is less than 0.05S, considers blow-out wake flow (such as oil-break) 0.02S, Microcomputer Protection dress The reaction time put is less than 0.02s, and safety allowance 0.01s, and it is 0.1s to take the time differential.If total drop station outlet breaker Ground connection specified time quick-break takes 0.5S, you can realizes 5 grades of cooperations, it is sufficient to meets general power supply needs.
The implementation of 4.3 tripping operations, is specifically included：
4.3.1 the trip method of electric shock quick-break circuit
All breakers when ground connection occurs from earth point to mains side flow through identical resistor current, will start simultaneously The concurrent loop ground connection alarm signal of zero sequence overcurrent element of corresponding protective relaying device.Ground connection occurs to begin in 0.07S, presets and want Tripping operation have Danger Electric shock risk or permanent earth and the circuit containing high pay-off target should trip.
4.3.2 the trip method of ungrounded quick-break circuit
After 0.1s occurs for system earth failure, grounding resistance exits, arc suppression coil starts to automatically adjust, until earth fault Processing (two hours troubleshooting time limits) finishes；If earth fault does not disappear but arc suppression coil works more than 2 hours, thrown by code Enter grounding resistance, relay protection system zero-sequenceprotection action, temporally differential order, control distance fault point is nearest in 0.5s Switch tripping operation excision at first trouble point.In addition, to exclude influence, mitigation of the high pass resistance Y points ground connection to earth-fault current Arc suppression coil output load, in the case where earth point earth current harmonic content does not cause arc reignition, Y points can be grounded Suspended when resistance exits, arc suppression coil works；Reclosing can be designed to improve confession during the overhead transmission line ground connection easily influenceed by weather Electric reliability.
Below by way of an instantiation, the application of the control method of the system of the present invention is introduced, it is specific as follows：
Referring specifically to Fig. 8, it is the flow chart of the steady prosecutor method of distributed generation system off-grid of the present invention.
The control method of the present invention is applied in distributed generation system by the present embodiment, steady so as to provide a kind of off-grid Prosecutor method, realize following effect：
A, distinguish that grid-connected interconnection occurs ground connection and takes transfer load, adjustment generator output when system earth occurs System risk is reduced Deng preventive measure；
Grid-connected interconnection trip command signal is distributed by protective relaying device at once when b. distinguishing and developing into phase short circuit accident To generator adjusting means, reactive generating device and active absorption plant, make full use of the intrinsic opening time of breaker (qualified true The empty breaker open operation time is less than 50ms) be used as lead, power surplus amount when controlling off-grid transient state, prevent Generation Side idle and Active accumulation causes voltage, frequency significantly to vibrate out-of-limit and unstability, realizes isolated power grid, helps solve wind-power electricity generation low-voltage Pass through and the problems such as small power station's off-grid driving.
To sum up, it is of the invention by filtering compensation equipment, grounding apparatus, PT harmonic elimination apparatus and relay compared to prior art The fusion of protection device function is got up, and is playing the compensation of capacitance reactive compensation device and the ground connection of filter function, earthing or grounding means Leakage path over the ground is provided at any time for resonant energy while security function and realizes direct harmonic elimination, and can play relay protection system Ground connection control function.
Above-described embodiment is the preferable embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment Limitation, other any Spirit Essences without departing from the present invention with made under principle change, modification, replacement, combine, simplification, Equivalent substitute mode is should be, is included within protection scope of the present invention.

Claims (3)

  1. A kind of 1. all-pass wave filtering harmonic elimination structure for medium voltage network system, it is characterised in that：Including low pass inductance LL, low pass electricity Hinder RL, grounding resistance Re, asterism ground connection throwing back out close K, high pass electric capacity CH, high pass resistance RH, basic-frequency branch inductance L1With fundamental frequency branch Road electric capacity C1；
    The low pass inductance LLOne end be used to be sequentially connected with the system power supply of medium voltage network and load connection, the other end simultaneously Low-pass resistors RL, grounding resistance ReBacked out with asterism ground connection throwing and close K；
    The high pass electric capacity CHOne end be used to be sequentially connected with the system power supply of medium voltage network and load connection, the other end simultaneously Basic-frequency branch inductance L1With basic-frequency branch electric capacity C1；The high pass electric capacity CHWith basic-frequency branch inductance L1Tie point be sequentially connected The high pass resistance RH, grounding resistance Re and asterism ground connection throwing back out close K.
  2. 2. it is used for the all-pass wave filtering harmonic elimination structure of medium voltage network system according to claim 1, it is characterised in that：The fundamental frequency Shunt inductance L1Impedance and basic-frequency branch electric capacity C1Capacitive reactance it is identical, i.e. XL1=XC1；The high pass resistance RHThe three-phase of extraction The controllable ground connection of star contact.
  3. A kind of 3. ground connection control method realized by relay protection system for medium voltage network system, applied to such as claim The 1 all-pass wave filtering harmonic elimination structure for being used for medium voltage network system, comprises the following steps：
    S1：Carry out system is initially set, and input asterism ground connection throwing, which is backed out, closes K, and juxtaposition arc suppression coil output current is minimum；
    S2：Signal acquisition is carried out, the signal includes：Voltage, electric current, frequency, switching value and instruction；
    S3：Judge whether to meet that system earth, circuit zero-sequence current reach setting valve simultaneously；If so, then perform next step；If It is no, then return to step S1；
    S4：Judge whether the ground connection quick-break circuit of setting, if performing step S5；If it is not, then perform step S51 and S52 simultaneously；
    S5：Ground path quick-break, return to step S1；
    S51：Delay 0.1 second, then perform following steps simultaneously：
    S511：Exit asterism ground connection throwing and back out pass K；
    S512：Judge the whether super predetermined value of earth current harmonic content, perform S521 if not；
    S52：Put into arc suppression coil and adjust to setting definite value：Earth point Fundamental-frequency Current is minimum；And following steps are performed simultaneously：
    S521：Judge arc suppression coil load whether super predetermined value, if so, then by high pass resistance RHThree-phase star contact be arranged to outstanding Floating state；
    S522：Search earth point, eliminate earth fault；
    S523：Judge whether ground connection disappears, if so, then return to step S1；If it is not, then perform step S6；
    S524：After delay 2 hours, step S6 is performed；
    S6：Judge whether to meet that system earth and circuit zero-sequence current reach setting valve and reach delay time simultaneously, Huo Zheshou To artificial trip command, if performing step S7；
    S7：Ground path delay tripping, return again to step S1.
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CN108768093B (en) * 2018-05-25 2020-04-07 长江勘测规划设计研究有限责任公司 Impedance type neutral point grounding method for giant hydroelectric generating set
CN109884465B (en) * 2019-03-01 2023-09-29 辽宁工业大学 Unidirectional ground fault positioning method based on signal injection method
CN110837014B (en) * 2019-11-01 2021-07-20 国网新疆电力有限公司哈密供电公司 Detection method and system for judging whether harmonic voltage amplification is caused by grounding

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1132953A (en) * 1965-03-27 1968-11-06 Asea Ab Improvements in static electrical converter stations
CN1215946A (en) * 1998-09-29 1999-05-05 北京电力设备总厂电器分厂 Wave damper tuning circuit design method and wave damper tuning circuit
CN1239345A (en) * 1999-06-16 1999-12-22 北京电力设备总厂 Design method of carrier-filter joint circuit for power transmission line and its joint filter circuit
CN1369135A (en) * 1999-08-03 2002-09-11 艾利森电话股份有限公司 Analog filter
CN103718441A (en) * 2011-08-04 2014-04-09 Abb技术有限公司 Transformerless multilevel converter
CN105048795A (en) * 2014-04-24 2015-11-11 英飞凌科技奥地利有限公司 Enhanced power factor correction

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1132953A (en) * 1965-03-27 1968-11-06 Asea Ab Improvements in static electrical converter stations
CN1215946A (en) * 1998-09-29 1999-05-05 北京电力设备总厂电器分厂 Wave damper tuning circuit design method and wave damper tuning circuit
CN1239345A (en) * 1999-06-16 1999-12-22 北京电力设备总厂 Design method of carrier-filter joint circuit for power transmission line and its joint filter circuit
CN1369135A (en) * 1999-08-03 2002-09-11 艾利森电话股份有限公司 Analog filter
CN103718441A (en) * 2011-08-04 2014-04-09 Abb技术有限公司 Transformerless multilevel converter
CN105048795A (en) * 2014-04-24 2015-11-11 英飞凌科技奥地利有限公司 Enhanced power factor correction

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