CN1996697A - Relay protection method of the line single phase grounding failure affected by the distribution-resisting capacitance and current - Google Patents

Abstract

This invention belongs to power system relay protection field and relates to anti-distribution capacitor current single phase earth fault relay protection method, which comprises each phase voltage, current, zero order voltage and current in the transducer station as input voltage, wherein, it uses measurement voltage and current to compute reactor Relay measurement voltage and current proportion; according to circuit distribution parameter to compute resistance integral value; using measurement resistance and integral vale to get relative operation base.

Description

The relay protecting method of the line single phase grounding failure of anti-capacitance current influence

Technical field

The invention belongs to field of relay protection in power, particularly a kind of relay protecting method based on the accurate ultra-high-tension power transmission line single phase ground fault of measuring of short-circuit impedance.

Background technology

Distance protection obtains extensive use in the circuit on power system protection, impedance relay is the measuring component in the distance protection.Because the Power System Shortcuts type is more, need react dissimilar faults respectively with different impedance relays.For example: the alternate impedance relay of the impedance ground relay of reaction ground short circuit and reaction phase fault.Impedance ground relay commonly used at present mainly contains following several: 1. round characteristic impedance relay; 2. quadrilateral characteristics impedance relay; 3. linear characteristic impedance relay.

No matter the impedance relay of which kind of operating characteristics all is sizes of measuring impedance by calculating, reacts Power System Shortcuts point to the distance of protecting the installation place, and determines whether sending actuating signal according to the distance of short circuit distance.For the metallic earthing fault, if ignore the existence that line distribution capacitance, electricity are led, the measurement impedance of impedance relay equals the product of short circuit distance and circuit unit's resistance value, i.e. short circuit distance is with to measure impedance proportional.For through transition grounding through resistance fault, the measurement impedance of impedance relay will be subjected to the influence of transition resistance; Short circuit this moment distance is set up substantially with the proportional relationship of measuring impedance, and the impedance relay of different qualities has different anti-transition resistance abilities.

Hence one can see that, and the correct operation of traditional impedance relay is based on a prerequisite: ' distributed capacitance of circuit, electricity are led and can be ignored, and the current value that flows through on the arbitrary unit long transmission line equates '.Just be based on this prerequisite, just can derive the metallicity fault after, the measurement resistance value of impedance relay and short circuit distance is proportional.If consider the existence that distributed capacitance, electricity are led in the circuit model, because the shunting action that distributed capacitance, electricity are led, the current value that flows through on arbitrary unit length circuit is no longer equal, and the measurement resistance value of the impedance ground relay at circuit top also no longer equals the product of short circuit distance and circuit unit's resistance value.This shows that owing to the existence that distributed capacitance, electricity are led, the prerequisite of traditional impedance ground relay work is no longer set up, relay can't correctly be distinguished the fault point and be positioned at outside district or the district, can't guarantee selectivity.

The electric derivative value of transmission line is very little, and is also very little to the measurement impedance value influence of impedance relay, can ignore substantially.For distributed capacitance; high pressure (110kV, 220kV), superhigh pressure (330kV, 500kV) transmission line electric pressure are not high; particularly transmission line length is lacked (can not surpass 500km); distributed capacitance is little to the influence of impedance relay; generally be lower than 4% of protection range; substantially can ignore or can adjust by protection and compensate, therefore the impedance ground relay can satisfy actual needs substantially at present.But for the UHV transmission line more than the 750kV (1000kV, 1150kV), typical case's transmission of electricity radius is 800km to 1000km, and the influence of distributed capacitance can not be ignored again; This moment, the prerequisite of traditional impedance ground relay work was no longer set up, and correctly new guard method must be developed in the failure judgement position.

Summary of the invention

The objective of the invention is for overcoming the weak point of prior art, a kind of relay protecting method of line single phase grounding failure of anti-capacitance current influence has been proposed, the present invention can accurately describe the physical characteristic of transmission line, accurately calculate the size of short-circuit impedance, have the ability of natural anti-capacitance current influence; Use the impedance relay of the inventive method and compare with traditional impedance relay, performance significantly improves, and satisfies the requirement of selectivity of relay protection, reliability, sensitivity and quick-action.

The present invention proposes a kind of relay protecting method of line single phase grounding failure of anti-capacitance current influence, may further comprise the steps:

1, measurement circuitry is at each phase voltage of transforming plant protecting installation place, each phase current, residual voltage and zero-sequence current, as input variable, that is:

A phase: A phase voltage

The A phase current Residual voltage Zero-sequence current

B phase: B phase voltage The B phase current Residual voltage

Zero-sequence current

C phase: C phase voltage The C phase current

Residual voltage Zero-sequence current

2, utilize measuring voltage and measurement electric current, calculating is measured impedance and is:

1) measuring voltage

Wherein:

Be phase voltage;

2) measure electric current

Wherein: Be phase current;

$P_1=\frac{Z_{c0}}{Z_{c1}}\left(\frac{T\·\mathrm{ch}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}+\mathrm{sh}{\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}-T\·\mathrm{ch}{\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}}{\mathrm{sh}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}}\right)-1$

P ₁Be zero sequence current compensation factor based on the circuit distributed constant, wherein:

Z _C1Be the positive sequence wave impedance: $Z_{c1}=\sqrt{(R_1+\mathrm{j\ω}{L}_1)/(G_1+\mathrm{j\ω}{C}_1)},$ R ₁, L ₁, G ₁, C ₁The positive sequence resistance, inductance, the electricity that are respectively the unit length circuit are led and capacitance;

Z _C0Be the zero sequence wave impedance: $Z_{c0}=\sqrt{(R_0+\mathrm{j\ω}{L}_0)/(G_0+\mathrm{j\ω}{C}_0)},$ R ₀, L ₀, G ₀, C ₀The zero sequence resistance, inductance, the electricity that are respectively the unit length circuit are led and capacitance;

Be the positive sequence propagation coefficient: ${\stackrel{\·}{\mathrm{\γ}}}_1=\sqrt{(R_1+\mathrm{j\ω}{L}_1)(G_1+\mathrm{j\ω}{C}_1)};$

Be the zero sequence propagation coefficient: ${\stackrel{\·}{\mathrm{\γ}}}_0=\sqrt{(R_0+\mathrm{j\ω}{L}_0)(G_0+\mathrm{j\ω}{C}_0)};$

l _ZdBe route protection scope setting value;

T is the system equivalent zero sequence impedance based on distributed parameter model: $T=\frac{{\stackrel{\·}{U}}_0}{Z_{c0}{\stackrel{\·}{I}}_0};$

With P ₁The computing formula linearisation of value obtains P value computing formula and is:

$P=\frac{Z_{c0}}{Z_{c1}}\·\frac{{\left({\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}\right)}^3+T\·3({\left({\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right)}^2-{\left({\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}\right)}^2)+6{\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}}{{\left({\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right)}^3+6{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}}-1$

3) measure impedance Z _RelayEqual measuring voltage and the ratio of measuring electric current: $Z_{\mathrm{relay}}=\frac{{\stackrel{\·}{U}}_{\mathrm{relay}}}{{\stackrel{\·}{I}}_{\mathrm{relay}}};$

3, according to Transmission Line Distributed Parameter computing impedance setting value be $Z_{\mathrm{set}}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}};$

4,, utilize and measure impedance Z according to the operating characteristics of different relays _RelayWith impedance setting value Z _SetObtain the corresponding action criterion:

1) whole impedance relay:

Amplitude comparison criterion: | Z _Relay|≤| Z _Set|;

Or phase place comparison criterion:

2) mho-impedance relay:

Amplitude comparison criterion: $|Z_{\mathrm{relay}}-\frac{1}{2}{Z}_{\mathrm{set}}|\≤\left|\frac{1}{2}{Z}_{\mathrm{set}}\right|;$

Or phase place comparison criterion:

3) skew circle impedance relay:

Amplitude comparison criterion: $|Z_{\mathrm{relay}}-\frac{1}{2}(Z_{\mathrm{set}1}+Z_{\mathrm{set}2})|\≤\left|\frac{1}{2}(Z_{\mathrm{set}1}-Z_{\mathrm{set}2})\right|,$ Z _Set1Be positive direction adjust impedance, Z _Set2Be the impedance of adjusting in the other direction;

Or phase place comparison criterion:

4) apple shape characteristic impedance relay:

Phase place comparison criterion: $-\mathrm{\β}\≤\arg \frac{Z_{\mathrm{set}}-Z_{\mathrm{relay}}}{Z_{\mathrm{relay}}}\≤\mathrm{\β},$ β 〉=90 ° wherein;

5) olive shape characteristic impedance relay:

Phase place comparison criterion: $-\mathrm{\β}\≤\arg \frac{Z_{\mathrm{set}}-Z_{\mathrm{relay}}}{Z_{\mathrm{relay}}}\≤\mathrm{\β},$ β≤90 ° wherein;

6) reactance characteristic impedance relay:

Amplitude comparison criterion: | Z _Relay|≤| Z _Relay-j2X _Set|, X _SetReactive component for the impedance setting value;

Or phase place comparison criterion:

7) directional characteristic impedance relay:

Amplitude comparison criterion: | Z _Relay-Z _Set|≤| Z _Relay+ Z _Set|

Or phase place comparison criterion:

8) quadrilateral characteristics impedance relay:

Phase place comparison criterion is the common factor of following three equations:

X wherein _SetBe the relay positive direction reactive component of impedance of adjusting; R _SetRelay setting resistance value for the reaction part throttle characteristics; Z _Set2Be the impedance of adjusting in the other direction; α ₁, α ₂, α ₃, α ₄Be the operating characteristics angle of adjusting;

5, no matter which kind of operating characteristics impedance relay adopts, as long as amplitude comparison criterion or phase place comparison criterion are set up, then trip signal is sent out in the protection action; Otherwise protection is failure to actuate.

Characteristics of the present invention and technique effect:

Characteristics of the present invention are: the inventive method is based on the Transmission Line Distributed Parameter model and proposes, and can accurately describe the physical characteristic of transmission line, accurately calculates the size of short-circuit impedance, has the ability of natural anti-capacitance current influence; The inventive method is applicable to the transmission line of any electric pressure; especially for the transmission of electricity of the ultra-high/extra-high voltage more than 750kV long transmission line (1000kV, 1150kV); using the impedance relay of the inventive method compares with traditional impedance relay; performance significantly improves, and satisfies the requirement of selectivity of relay protection, reliability, sensitivity and quick-action.

Description of drawings

Fig. 1 is for using the system for ultra-high voltage transmission schematic diagram of the inventive method.

Fig. 2 is the impedance relay performance based on traditional impedance relay of model shown in Figure 1 and application the inventive method; Wherein:

(a) be the performance of traditional mho-impedance relay;

(b) be the performance of using the mho-impedance relay of the inventive method;

(c) be the performance of traditional reactance characteristic impedance relay;

(d) be the performance of using the reactance characteristic impedance relay of the inventive method;

(e) be the performance of conventional direction characteristic impedance relay;

(f) be the performance of using the directional characteristic impedance relay of the inventive method.

Embodiment

The relay protecting method embodiment of the line single phase grounding failure of the anti-capacitance current influence that the present invention proposes is described in detail as follows:

Use a kind of 1000kV system for ultra-high voltage transmission type of the present invention as shown in Figure 1, the line parameter circuit value value is as shown in table 1.Line length is 800km.The both sides system impedance is as follows, and N side power supply angle falls behind M side 44 degree, and M side and N side electromotive force are respectively 1.1062 and 1.1069 times of rated voltages.With the protection of M side is example, and voltage, electric current are respectively from line side voltage transformer (PT), current transformer (CT).

Table 1 1000kV UHV transmission line major parameter

Line parameter circuit value	Resistance (Ω/km)	Reactance (Ω/km)	Capacitive reactance (M Ω/km)
				The positive sequence zero sequence	0.00805 0.20489	0.25913 0.74606	0.22688 0.35251

Both sides system impedance parameter is:

M side positive sequence system impedance: Z _M1=4.2643+j85.14528 Ω

M side zero sequence system impedance: Z _M0=98.533+j260.79 Ω

N side positive sequence system impedance: Z _N1=7.9956+j159.6474 Ω

N side zero sequence system impedance: Z _N0=184.749+j488.981 Ω

The relay protecting method of the line single phase grounding failure of the anti-capacitance current influence that the present invention proposes is applicable to any a section of distance protection.Present embodiment is an evaluating objects with distance protection I section, and protection range is adjusted and is 80% (l of total track length _Zd=640), the emulation fault is the A of a 610km place phase metallic earthing fault, and then the embodiment concrete steps are as follows:

1, measurement circuitry is as follows at transforming plant protecting installation place A phase voltage, A phase current, residual voltage and zero-sequence current:

The A phase voltage ${\stackrel{\·}{U}}_a=-0.597-j\·0.0761\mathrm{MV}$

The A phase current ${\stackrel{\·}{I}}_a=-1.684+j\·1.391\mathrm{kA}$

Residual voltage ${\stackrel{\·}{U}}_0=0.289-j\·0.263\mathrm{MV}$

Zero-sequence current ${\stackrel{\·}{I}}_0=0.516+j\·1.304\mathrm{kA}$

2, utilize measuring voltage and measurement electric current, calculating is measured impedance and is:

1) measuring voltage ${\stackrel{\·}{U}}_{\mathrm{relay}}={\stackrel{\·}{U}}_a=-0.597-j\·0.0761\mathrm{MV};$

2) utilize table 1 data, calculate:

The positive sequence wave impedance $Z_{c1}=\sqrt{(R_1+\mathrm{j\ω}{L}_1)/(G_1+\mathrm{j\ω}{C}_1)}=242.5-j\·3.766$

The zero sequence wave impedance $Z_{c0}=\sqrt{(R_0+\mathrm{j\ω}{L}_0)/(G_0+j{\mathrm{\ωC}}_0)}=517.55-j\·69.775$

The positive sequence propagation coefficient ${\stackrel{\·}{\mathrm{\γ}}}_1=\sqrt{(R_1+\mathrm{j\ω}{L}_1)(G_1+\mathrm{j\ω}{C}_1)}=j\·0.0011$

The zero sequence propagation coefficient: ${\stackrel{\·}{\mathrm{\γ}}}_0=\sqrt{(R_0+\mathrm{j\ω}{L}_0)(G_0+\mathrm{j\ω}{C}_0)}=0.0002+j\·0.0015$

Utilize zero-sequence current, voltage and zero sequence wave impedance value, calculate T: $T=\frac{{\stackrel{\·}{U}}_0}{Z_{c0}{\stackrel{\·}{I}}_0}=-0.12-j\·0.52$

Bring the aforementioned calculation result into P value computing formula, ask for the P value and be:

$P=\frac{Z_{c0}}{Z_{c1}}\·\frac{{\left({\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}\right)}^3+T\·3{\left({\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right)}^2-{\left({\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}\right)}^2+6{\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}}{{\left({\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right)}^3+6{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}}-1=1.478-j\·0.274$

Therefore, obtain measuring electric current

3) calculate the measurement impedance $Z_{\mathrm{relay}}=\frac{{\stackrel{\·}{U}}_{\mathrm{relay}}}{{\stackrel{\·}{I}}_{\mathrm{relay}}}=9.165+j\·186.31\mathrm{\Ω}$

3, according to Transmission Line Distributed Parameter computing impedance setting value be $Z_{\mathrm{set}}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}=7.358+j\·197.63$

4, the operating criterion of more different operating characteristics impedance relays:

1) whole impedance relay

|Z _set|＝|7.358+j·197.63|＝197.77，|Z _relay|＝|9.165+j·186.31|＝186.54

2) mho-impedance relay

$|Z_{\mathrm{relay}}-\frac{1}{2}{Z}_{\mathrm{set}}|=87.67$

$\left|\frac{1}{2}{Z}_{\mathrm{set}}\right|=\frac{1}{2}\·|7.538+j\·197.63|=98.88$

3) skew circle impedance relay

The positive direction impedance of adjusting $Z_{\mathrm{set}1}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}=7.358+j\·197.63$

Adjust in the other direction and be 10% of protected circuit total length, i.e. l _{Zd_inverse}=80, and direction is reverse, therefore,

$Z_{\mathrm{set}2}=-Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}\_\mathrm{inverse}}=-0.647-j\·20.781$

$|Z_{\mathrm{relay}}-\frac{1}{2}(Z_{\mathrm{set}1}+Z_{\mathrm{set}2})|=97.55$

$\left|\frac{1}{2}(Z_{\mathrm{set}1}-Z_{\mathrm{set}2})\right|=108.77$

4) apple shape characteristic impedance relay

Adjust β=120 °,

$\arg \frac{Z_{\mathrm{set}}-Z_{\mathrm{relay}}}{Z_{\mathrm{relay}}}=11.88$

5) olive shape characteristic impedance relay

Adjust β=60 °,

$\arg \frac{Z_{\mathrm{set}}-Z_{\mathrm{relay}}}{Z_{\mathrm{relay}}}=11.88$

6) reactance characteristic impedance relay

X _SetReactive component for the impedance setting value: X _Set=197.63

|Z _relay|＝|9.165+j·186.31|＝186.54

|Z _relay-j·2X _set|＝209.15

7) directional characteristic impedance relay

|Z _relay-Z _set|＝11.46

|Z _relay+Z _set|＝384.30

8) quadrilateral characteristics impedance relay

X _set＝197.63

$Z_{\mathrm{set}2}=-Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}\_\mathrm{inverse}}=-0.647-j\·20.781$

α ₁＝α ₂＝14°、α ₃＝45°、α ₄＝7.1°

R _SetBe the relay setting resistance value of reaction part throttle characteristics, it is adjusted and is half of line impedance value in the distance protection I segment protect scope, that is: $R_{\mathrm{set}}=0.5\·\left|Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right|=98.884$

Thereby, calculate:

$\arg \frac{Z_{\mathrm{relay}}-j\·X_{\mathrm{set}}}{-j\·X_{\mathrm{set}}}=39.0$

$\arg \frac{Z_{\mathrm{relay}}-R_{\mathrm{set}}}{-R_{\mathrm{set}}}=-64.29$

$\arg \frac{Z_{\mathrm{relay}}-Z_{\mathrm{set}2}}{R_{\mathrm{set}}}=87.29$

5, according to the result of calculation in the 4th step, the amplitude comparison criterion of more different operating characteristics impedance relays or phase place comparison criterion are all set up, and therefore trip signal is sent out in the protection action.

In order to check the performance of traditional impedance relay and the impedance relay of using the inventive method, the present invention has been carried out a large amount of Digital Simulations, the fault point is selected to be decremented to 550km gradually from 790km, and step-length is 1km.

The measurement data and the action logic of mho-impedance relay are as shown in table 2, as space is limited, and (the simulation result of 630km～650km) when only having provided protection I segment boundary near fault.Wherein ' actuating quantity ' is defined as

' braking amount ' expression

Action logic ' 1 ' expression relay tripping operation excision fault, ' 0 ' expression relay is failure to actuate.

Table 2 mho-impedance relay partial simulation result

Fault distance	Measuring voltage		Measure electric current		Measure impedance		Actuating quantity	The braking amount	Action logic
										Duplicate (MV)	Phase angle (degree)	Amplitude (kA)	Phase angle (degree)	Amplitude (Ω)	Phase angle (degree)
	650	0.6200	-172.48	3.0586	99.138	202.715										88.379	98.883	103.840	0
649							0.6197	-172.48	3.0628	99.164	202.338	88.357	98.883	103.462	0
	648	0.6191	-172.48	3.0669	99.201	201.852										88.313	98.883	102.975	0
647							0.6187	-172.49	3.0711	99.227	201.474	88.274	98.883	102.596	0
	646	0.6184	-172.51	3.0755	99.252	201.075										88.237	98.883	102.196	0
645							0.6179	-172.55	3.0797	99.277	200.647	88.170	98.883	101.767	0
	644	0.6173	-172.59	3.0838	99.300	200.173										88.107	98.883	101.292	0
643							0.6163	-172.58	3.0882	99.326	199.568	88.086	98.883	100.687	0
	642	0.6156	-172.55	3.0925	99.346	199.068										88.096	98.883	100.187	0
641							0.6154	-172.54	3.0964	99.364	198.760	88.095	98.883	99.878	0
	640	0.6153	-172.58	3.1003	99.387	198.460										88.031	98.883	99.577	0
639							0.6148	-172.59	3.1046	99.413	198.034	87.987	98.883	99.152	0
	638	0.6142	-172.60	3.1089	99.433	197.574										87.965	98.883	98.691	1
637							0.6138	-172.58	3.1130	99.457	197.183	87.965	98.883	98.300	1
	636	0.6135	-172.62	3.1170	99.484	196.813										87.897	98.883	97.930	1
635							0.6127	-172.61	3.1212	99.510	196.312	87.878	98.883	97.429	1
	634	0.6123	-172.60	3.1249	99.530	195.955										87.870	98.883	97.073	1
633							0.6123	-172.61	3.1293	99.549	195.660	87.835	98.883	96.777	1
	632	0.6116	-172.64	3.1338	99.587	195.151										87.776	98.883	96.268	1
631							0.6112	-172.62	3.1377	99.599	194.786	87.784	98.883	95.903	1
	630	0.6109	-172.62	3.1424	99.630	194.419										87.746	98.883	95.537	1

Fig. 2 has provided different operating characteristics impedance relays, along with the action situation of fault distance variation.Ordinate is an actuating quantity (the right side part of amplitude comparison criterion inequality) and the difference of braking amount (left part of amplitude comparison criterion inequality) among the figure, and wherein on the occasion of the expression actuating of relay, negative value represents that relay is failure to actuate.

By Fig. 2-(a) can see; the tradition mho-impedance relay can only protect about 585km apart from the I section; and shown in Fig. 2-(b), the mho-impedance relay of using the inventive method can be protected (640km) near the relay setting, and relay performance is greatly improved.Whole impedance relay, skew circle impedance relay, apple shape characteristic impedance relay, olive shape characteristic impedance relay belong to round characteristic impedance relay, its operating characteristics and mho-impedance relay operating characteristics are similar, the positive direction setting value is identical, the performance of relay all can be embodied by Fig. 2-(a) and (b), no longer provides simulation result at this.

Fig. 2-(c), (d) are the performance of reactance characteristic impedance relay, can see and using near the actuating range of reactance characteristic impedance relay has been increased to 640km from 605km behind the present invention that relay performance is greatly improved.Because in fact the fault distance discriminating element of quadrangle impedance relay is exactly the reactance characteristic impedance relay, so Fig. 2-(d) has also embodied the good operating characteristics of using quadrangle impedance relay after the inventive method.

Fig. 2-(e), (f) have provided the performance of directional characteristic impedance relay, because the emulation fault selects to be the forward fault, so conventional direction characteristic impedance relay and the equal energy of application directional characteristic impedance relay of the present invention correct operation, but clearly, the directional characteristic impedance relay actuating quantity difference of using the inventive method is bigger, and the actuating of relay is more reliable.

Claims (1)

1, a kind of relay protecting method of line single phase grounding failure of anti-capacitance current influence may further comprise the steps:

1) measurement circuitry is at each phase voltage of transforming plant protecting installation place, each phase current, residual voltage and zero-sequence current, as input variable, that is:

A phase: A phase voltage

The A phase current Residual voltage

Zero-sequence current

B phase: B phase voltage The B phase current

Residual voltage Zero-sequence current

C phase: C phase voltage The C phase current

Residual voltage Zero-sequence current

2) utilize measuring voltage and measurement electric current, calculating is measured impedance and is:

(1) measuring voltage Wherein:

Be phase voltage;

(2) measure electric current

Wherein:

Be phase current;

$P_1=\frac{Z_{c0}}{Z_{c1}}\left(\frac{T\·\mathrm{ch}{\stackrel{.}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}+\mathrm{sh}{\stackrel{.}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}-T\·\mathrm{ch}{\stackrel{.}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}}{\mathrm{sh}{\stackrel{.}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}}\right)-1$

P ₁Be zero sequence current compensation factor based on the circuit distributed constant, wherein:

Z _C1Be the positive sequence wave impedance: $Z_{c1}=\sqrt{(R_1+\mathrm{j\ω}{L}_1)/(G_1+\mathrm{j\ω}{C}_1)},$ R ₁, L ₁, G ₁, C ₁The unit of being respectively

The positive sequence resistance of length circuit, inductance, electricity are led and capacitance;

Z _C0Be the zero sequence wave impedance: $Z_{c0}=\sqrt{(R_0+\mathrm{j\ω}{L}_0)/(G_0+\mathrm{j\ω}{C}_0)},$ R ₀, L ₀, G ₀, C ₀The unit of being respectively

The zero sequence resistance of length circuit, inductance, electricity are led and capacitance;

Be the positive sequence propagation coefficient: ${\stackrel{.}{\mathrm{\γ}}}_1=\sqrt{(R_1+\mathrm{j\ω}{L}_1)(G_1+\mathrm{j\ω}{C}_1)};$

Be the zero sequence propagation coefficient: ${\stackrel{.}{\mathrm{\γ}}}_0=\sqrt{(R_0+\mathrm{j\ω}{L}_0)(G_0+\mathrm{j\ω}{C}_0)};$

l _ZdBe route protection scope setting value;

T is the system equivalent zero sequence impedance based on distributed parameter model: $T=\frac{{\stackrel{.}{U}}_0}{Z_{c0}{\stackrel{.}{I}}_0};$

With P ₁The computing formula linearisation of value obtains P value computing formula and is:

$P=\frac{Z_{c0}}{Z_{c1}}\·\frac{{\left({\stackrel{.}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}\right)}^3+T\·3({\left({\stackrel{.}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right)}^2-{\left({\stackrel{.}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}\right)}^2)+6{\stackrel{.}{\mathrm{\γ}}}_0{l}_{\mathrm{zd}}}{{\left({\stackrel{.}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}\right)}^3+6{\stackrel{.}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}}}-1$

(3) measure impedance Z _RelayEqual measuring voltage and the ratio of measuring electric current: $Z_{\mathrm{relay}}=\frac{{\stackrel{.}{U}}_{\mathrm{relay}}}{{\stackrel{.}{I}}_{\mathrm{relay}}};$

3) according to Transmission Line Distributed Parameter computing impedance setting value be $Z_{\mathrm{set}}=Z_{\mathrm{cl}}\mathrm{th}{\stackrel{.}{\mathrm{\γ}}}_1{l}_{\mathrm{zd}};$

4), utilize and measure impedance Z according to the operating characteristics of different relays _RelayWith impedance setting value Z _SetObtain the corresponding action criterion:

(1) whole impedance relay:

Amplitude comparison criterion: | Z _Relay|≤| Z _Set|;

Or phase place comparison criterion:

(2) mho-impedance relay:

Amplitude comparison criterion: $|Z_{\mathrm{relay}}-\frac{1}{2}{Z}_{\mathrm{set}}|\≤\left|\frac{1}{2}{Z}_{\mathrm{set}}\right|;$

Or phase place comparison criterion:

(3) skew circle impedance relay:

Amplitude comparison criterion: $|Z_{\mathrm{relay}}-\frac{1}{2}(Z_{\mathrm{set}1}+Z_{\mathrm{set}2})|\≤\left|\frac{1}{2}(Z_{\mathrm{set}1}-Z_{\mathrm{set}2})\right|,$ Z _Set1Be positive direction adjust impedance, Z _Set2Be the impedance of adjusting in the other direction;

Or phase place comparison criterion:

(4) apple shape characteristic impedance relay:

Phase place comparison criterion: $-\mathrm{\β}\≤\arg \frac{Z_{\mathrm{set}}-Z_{\mathrm{relay}}}{Z_{\mathrm{relay}}}\≤\mathrm{\β},$ β 〉=90 ° wherein;

(5) olive shape characteristic impedance relay:

Phase place comparison criterion: $-\mathrm{\β}\≤\arg \frac{Z_{\mathrm{set}}-Z_{\mathrm{relay}}}{Z_{\mathrm{relay}}}\≤\mathrm{\β},$ β 〉=90 ° wherein;

(6) reactance characteristic impedance relay:

Amplitude comparison criterion: | Z _Relay|≤| Z _Relay-j2X _Set|, X _SetReactive component for the impedance setting value;

Or phase place comparison criterion:

(7) directional characteristic impedance relay:

Amplitude comparison criterion: | Z _Relay-Z _Set|≤| Z _Relay+ Z _Set|

Or phase place comparison criterion:

(8) quadrilateral characteristics impedance relay:

Phase place comparison criterion is the common factor of following three equations:

X wherein _SetBe the relay positive direction reactive component of impedance of adjusting; R _SetRelay setting resistance value for the reaction part throttle characteristics; Z _SetBe the impedance of adjusting in the other direction; α ₁, α ₂, α ₃, α ₄Be the operating characteristics angle of adjusting;

5) which kind of operating characteristics no matter the impedance relay in the step 4) adopt, as long as amplitude comparison criterion or phase place comparison criterion are set up, then trip signal is sent out in the protection action; Otherwise protection is failure to actuate.

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