CN100526895C - Distributing capacitance current and transition resistance influence resisting line one-end fault ranging method - Google Patents

Abstract

The invention belongs to the electrical power system domain, specially relates to the line single end fault distance measuring method of the anti- distributed capacity electric current and the transition resistance influence. Including: surveys the transformer substation protection installment place fault phase voltage, the phase current, the zero sequence voltage, the zero sequence electric current and the negative sequence electric current as the input value; using the fault voltage cross zero time to measure the resistance characteristic which is not influence by transition resistance, from the protected line begin end start, computing the measure voltage real part computed value of the fault point voltage cross zero point time, compared with the measured value of the measure voltage real part, computing the error; and taking the delta-S as the step size, in turn computing the setting range which is protected by the send tripping signal, if cannot obtain the protect tripping signal, searching the total track length which is protected, taking the minimum point as the fault point. The invention method is not influenced by the distributed capacity electric current and transition resistance, does not have the false root problem of solving equation method and non convergence question of the iterative method, and has the very high practical value.

Description

The line one-end fault ranging method of anti-capacitance current and transition resistance influence

Technical field

The invention belongs to field of power, the line one-end fault ranging method of particularly a kind of anti-capacitance current and transition resistance influence.

Background technology

Transmission line of electricity is being undertaken the vital task that transmits electric energy, and its fault directly threatens the safe operation of electric system.Especially, the electric pressure of China develops to extra-high voltage (is representative with 1000kV) from UHV (ultra-high voltage) (is representative with 500kV), the transmission line of electricity capacity further increases, fault localization is got rid of line fault and is restored electricity as early as possible for quickening accurately, thereby the stability, the stable operation of assurance security of system that improve electric system have great importance.

Fault distance-finding method is divided into two kinds: single-ended method and both-end method from using the angle of electric parameters.The both-end method need be used the electric information at circuit two ends, can realize accurate localization of fault on the principle, but in actual applications, still is subjected to the influence of two ends sample frequency difference or phase deviation.Single-ended method does not need extra equipment, only adopts local electric parameters to carry out fault localization, is not subjected to the restriction of mechanics of communication, is the focus that industry is paid close attention to always.

The one-end fault ranging algorithm is divided into two classes from the angle of principle: impedance method and traveling wave method.Traveling wave method is realized fault localization by the time of measuring row wave-wave head commute between observation station and trouble spot, but the single-ended traveling wave method can not effectively be discerned the reflected traveling wave that comes from the trouble spot and come from the reflected traveling wave of other wave impedance discontinuous point, so the single-ended traveling wave method does not obtain the essence application.Impedance method: calculate observation station to the line impedance value between the trouble spot according to voltage, galvanometer after the fault, lead owing to ignored distributed capacitance, the electricity of transmission line of electricity, the proportional example relation of line impedance value and fault distance, thus realize localization of fault; But the single-ended impedance method can not be eliminated the influence of fault transition resistance and offside system impedance fully, precision is relatively poor than the both-end method, a lot of scholars are at this problem, proposed abundant the improving one's methods of kind, mainly contained: power frequency impedance method (1), separated Differential Equation Algorithm (2), zero-sequence current phase place revised law (3), fault current phase place revised law (4), separate quadratic equation method (5) etc.Method (1), (2) are assumed fault point electric current and observation station electric current same-phase all, method (3), (4), (5) all need known offside system impedance value, accurate localization of fault, yet system operation mode is changeable, be difficult to accurately obtain the peer-to-peer system resistance value, so the fault localization precision is not very high.But single-ended impedance fault localization algorithm does not need the information of offside, and is low to hardware requirement, is easy to realize; Though distance accuracy is not high, algorithm stability is fine, so has obtained at the scene using widely.The microcomputer protecting device of middle operation all adopts the single-ended impedance method as its fault localization element basically at the scene at present; utilize the stability of impedance method range finding simultaneously; the comprehensive combined method range finding of using single-ended impedance method and traveling wave method has also greatly promoted the performance that single-ended traveling wave is found range.

The single-ended impedance fault distance-finding method is widely used on high pressure (is representative with 220kV), supertension line, and its prerequisite is to think to measure impedance and the proportional example relation of fault distance that promptly the distributed capacitance of circuit can be ignored.This is because high pressure, supertension line length are generally less than 400km, and it is little to ignore the error that the influence of distributed capacitance brings, and can satisfy the requirement of rig-site utilization.And for the ultra-high/extra-high voltage long transmission line of the above electric pressure of 750kV, the electric current of the capacitance current of circuit and circuit transmission natural power is compared and can be reached more than 76%, and the error of still ignore distributed capacitance this moment, bringing with lumpy line Model Calculation fault distance can not be accepted by the scene.

Correlative study shows: with the distributed parameter transmission line model modeling, and the line impedance Z between observation station and the trouble spot _MeaBe the tanh relation with fault distance, that is: $Z_{\mathrm{mea}}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_{1}l,$ Z wherein _C1Be the positive sequence wave impedance,

Be the positive sequence propagation coefficient, they all are nonlinear functions of unit length line resistance, inductance, capacitance.The hyperbolic tangent function characteristic has determined its anti-transition resistance poor ability, and the additional measurement impedance that transition resistance brings will seriously influence the precision of fault localization.Traditional impedance method improvement project: carry out fault localization as adopting reactive component, partly eliminate the influence of transition resistance, no longer suitable for fault distance-finding method with the distributed parameter transmission line model modeling, mainly be because line impedance Z _MeaBe the nonlinear function of unit length line resistance, inductance, capacitance, be difficult to decoupling zero; Other scheme is as hypothesis peer-to-peer system impedance known or assumed fault point electric current and observation station electric current same-phase, on the ultra-high/extra-high voltage long transmission line of the above electric pressure of 750kV, the error of bringing can't be accepted, and therefore traditional single-ended impedance fault distance-finding method is difficult to be applied directly on the ultra-high/extra-high voltage long transmission line.

Summary of the invention

The objective of the invention is for overcoming the weak point of prior art, propose a kind of new anti-capacitance current and the line one-end fault ranging method of transition resistance influence, the physical model of this method adopts the distribution parameter modeling, is not subjected to the influence of capacitance current; This method utilizes fault point voltage zero crossing data computation constantly to measure resistance value, is not subjected to the influence of transition resistance; This method is a kind of method of search type, does not have the pseudo-root problem of the method for solving equation and the not convergence problem of process of iteration, has very high practical value.

The line one-end fault ranging method of a kind of anti-capacitance current that the present invention proposes and transition resistance influence may further comprise the steps:

1, measuring circuit is in transforming plant protecting installation place fault phase voltage phasor Fault phase current phasor

The residual voltage phasor The zero-sequence current phasor

The negative-sequence current phasor

As input quantity;

Wherein

For fault separate: A phase, B are mutually or the C phase;

2) calculating the fault point voltage zero crossing is constantly:

Wherein α is the initial phase angle of route protection installation place negative-sequence current, and ω is the specified angular frequency value of electric system;

3) calculate the fault point voltage zero crossing constantly, the real part measured value of protection installation place measuring voltage is:

Measuring voltage Wherein: U _RelayBe the measuring voltage amplitude, θ is the initial phase angle of measuring voltage; In the fault point voltage zero crossing moment, the real part measured value of measuring voltage is: U _{Mea_meter}=U _RelayCos (90 °-α+θ)

4) fault distance is taken as initial value l _Fault, calculate the protection installation place and measure electric current:

Measure electric current

Wherein: I _RelayFor measuring current amplitude, β is for measuring the initial phase angle of electric current;

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

P is the zero sequence current compensation factor based on the circuit distribution parameter, wherein:

Z _C1Be the positive sequence wave impedance: $Z_{c1}=\sqrt{(R_1+{\mathrm{j\ωL}}_1)/(G_1+{\mathrm{j\ωC}}_1)},$ 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: $Z_{c0}=\sqrt{(R_0+{\mathrm{j\ωL}}_0)/(G_0+{\mathrm{j\ωC}}_0)},$ 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: ${\stackrel{\·}{\mathrm{\γ}}}_1=\sqrt{(R_1+{\mathrm{j\ωL}}_1)(G_1+{\mathrm{j\ωC}}_1)};$

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

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

5) according to Transmission Line Distributed Parameter computational scheme resistance value Z _FaultFor:

$Z_{\mathrm{fault}}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{fault}}=Z_{\mathrm{relay}}(\cos (\mathrm{\ωt}+\mathrm{\τ})+j\sin (\mathrm{\ωt}+\mathrm{\τ}))$

Wherein: Z _RelayBe the line impedance amplitude, τ is the line impedance angle;

6) according to the fault point voltage zero crossing constantly, the real part calculated value of protection installation place measurement electric current and line impedance value calculating measuring voltage is:

U _{mea_cal}＝I _relayZ _relaycos(90°-α+τ+β)

7) calculating the real part calculated value of measuring voltage and the error of measured value is:

Error＝|U _{mea_cal}-U _{mea_meter}|

8) fault distance initial value l _FaultS increases one by one with step delta, return step 4), calculate the error amount of every bit successively, (setting range is according to the route protection of the relay protection national standard principle value of adjusting until the setting range of the protection of sending out trip signal, for example I section ground distance protection is sent out trip signal, and its setting range is 80% of a protected circuit total length; Total track length is 800km; then search procedure is that step-length increases to 640km one by one with Δ S), if can't be protected trip signal, then search for the protected circuit total length; the point of getting the error minimum is the trouble spot, and this distance to the route protection installation place is a fault distance.

Characteristics of the present invention and technique effect:

The inventive method is based on the proposition of Transmission Line Distributed Parameter model, can accurately describe the physical characteristics of transmission line of electricity, has the ability of natural anti-capacitance current influence; The inventive method is utilized fault point voltage zero crossing data computation fault distance constantly, is not subjected to the influence of transition resistance; The inventive method is a kind of method of search type, does not have the pseudo-root problem of the method for solving equation and the not convergence problem of process of iteration, has very high practical value.The inventive method is applicable to the transmission line of electricity of any electric pressure, especially for 750kV and above ultra-high/extra-high voltage transmission of electricity long transmission line, the fault localization precision of application the inventive method significantly improves than other one-end fault ranging method, can satisfy on-the-spot requirement.

Description of drawings

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

Fig. 2 compares based on the fault localization error characteristics of application of model the inventive method shown in Figure 1 and traditional power frequency impedance method fault localization error characteristics; Wherein:

(a) for using traditional power frequency impedance method fault localization error characteristics;

(b) for using the fault localization error characteristics of the inventive method;

Embodiment

The line one-end fault ranging method embodiment of anti-capacitance current that the present invention proposes and transition resistance influence 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, system is a typical both end power supplying system, and two side bus are respectively M and N, and line length is 800km, and the line parameter circuit value value is as shown in table 1.Both sides system impedance parameter 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.The fault location device of using the inventive method is installed in the M side, and voltage, electric current are respectively from line side voltage transformer (VT) (PT), current transformer (CT), and the positive dirction of electric current is electric current is flowed to circuit by bus a direction.

Table 1 1000kV UHV transmission line major parameter

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 line one-end fault ranging method that the present invention proposes is applicable to the range finding element and the fault location device independently of fault localization module, the fault oscillograph of any route protection.Present embodiment is an example with the fault localization module of using route protection of the present invention; with ground distance protection I section troubles inside the sample space is evaluating objects; protection domain adjust be 80% of total track length, emulation fault be the A of 420km place through 105 ohm of earth faults, the embodiment concrete steps are as follows:

1) measuring circuit is in transforming plant protecting installation place fault phase voltage phasor, phase current phasor, residual voltage phasor, zero-sequence current phasor, negative-sequence current phasor, and as input quantity, the present embodiment fault is the A phase mutually:

The A phase voltage ${\stackrel{\·}{U}}_a=-0.555+j\·0.110\mathrm{MV}$

The A phase current ${\stackrel{\·}{I}}_a=-2.799+j\·1.244\mathrm{kA}$

Residual voltage ${\stackrel{\·}{U}}_0=0.341-j\·0.128\mathrm{MV}$

Zero-sequence current ${\stackrel{\·}{I}}_0=-0.004+j\·1.307\mathrm{kA}$

Negative-sequence current ${\stackrel{\·}{I}}_2=-0.326+j\·0.827\mathrm{kA}$

2) the initial phase angle α of computational scheme protection installation place negative-sequence current is:

Then the fault point voltage zero crossing is constantly:

3) protection installation place measuring voltage is:

Then calculate the fault point voltage zero crossing constantly, the real part measured value of protection measuring voltage is:

U _{mea_meter}＝U _relaycos(90°-α+θ)＝0.566cos(-21.53°+168.76°)＝-0.476MV

4) fault distance is taken as initial value l _Fault=1km, calculate and protect installation place measurement electric current to be:

The positive sequence wave impedance: $Z_{c1}=\sqrt{(R_1+{\mathrm{j\ωL}}_1)/(G_1+{\mathrm{j\ωC}}_1)}=242.5-j\·3.766\mathrm{\Ω}$

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

The positive sequence propagation coefficient: ${\stackrel{\·}{\mathrm{\γ}}}_1=\sqrt{(R_1+{\mathrm{j\ωL}}_1)(G_1+{\mathrm{j\ωC}}_1)}=j\·0.0011$

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

Utilize zero-sequence current, voltage and zero sequence wave impedance value, calculate T: $T=\frac{{\stackrel{\·}{U}}_0}{Z_{c0}{\stackrel{\·}{I}}_0}=-0.121-j\·0.520$

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

$P=\frac{Z_{c0}}{Z_{c1}}\left(\frac{T\·\mathrm{ch}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{fault}}+\mathrm{sh}{\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{fault}}-T\·\mathrm{ch}{\stackrel{\·}{\mathrm{\γ}}}_0{l}_{\mathrm{fault}}}{\mathrm{sh}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{fault}}}\right)-1=1.901-j\·0.700$

Therefore, obtain measuring electric current:

5) according to Transmission Line Distributed Parameter computational scheme resistance value Z _FaultFor:

$Z_{\mathrm{fault}}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{fault}}=Z_{\mathrm{relay}}(\cos (\mathrm{\ωt}+\mathrm{\τ})+j\sin (\mathrm{\ωt}+\mathrm{\τ}))$

6, constantly, the real part calculated value of protection installation place measurement electric current and line impedance value calculating measuring voltage is according to the fault point voltage zero crossing:

U _{mea_cal}＝I _relayZ _relaycos(90°-α+τ+β)

＝4.182×0.259×cos(-21.53°+116.87°+88.209°)＝-0.0011MV

7) calculating the real part calculated value of measuring voltage and the error of measured value is:

Error＝|U _{mea_cal}-U _{mea_meter}|＝|-0.0011+0.476|＝0.4749MV

8) fault distance initial value l _Fault1km increases one by one with step-length, returns step 4, calculates the error amount of every bit successively, and until the setting range 640km of I section ground distance protection, then error amount is as shown in table 2:

The real part calculated value of table 2 measuring voltage and the error of measured value

Fault distance	Error amount (* 10 5V)	Fault distance	Error amount (* 10 5V)	Fault distance	Error amount (* 10 5V)	Fault distance	Error amount (* 10 5V)	Fault distance	Error amount (* 10 5V)	Fault distance	Error amount (* 10 5V)	Fault distance	Error amount (* 10 5V)
														1	4.750	93	3.758	185	2.760	277	1.741	369	0.681	461	0.442	553	0.166
2	4.740	94	3.747	186	2.749	278	1.730	370	0.669	462	0.455	554	0.167
														3	4.729	95	3.736	187	2.738	279	1.718	371	0.658	463	0.467	555	0.169
4	4.718	96	3.725	188	2.727	280	1.707	372	0.646	464	0.480	556	0.170
														5	4.707	97	3.715	189	2.716	281	1.696	373	0.634	465	0.493	557	0.172
6	4.696	98	3.704	190	2.705	282	1.684	374	0.622	466	0.506	558	0.173
														7	4.686	99	3.693	191	2.694	283	1.673	375	0.610	467	0.518	559	0.174
8	4.675	100	3.682	192	2.683	284	1.662	376	0.598	468	0.531	560	0.176
														9	4.664	101	3.671	193	2.672	285	1.651	377	0.586	469	0.544	561	0.177
10	4.653	102	3.661	194	2.662	286	1.639	378	0.575	470	0.557	562	0.179
														11	4.642	103	3.650	195	2.651	287	1.628	379	0.563	471	0.569	563	0.180
12	4.631	104	3.639	196	2.640	288	1.617	380	0.551	472	0.582	564	0.181
														13	4.621	105	3.628	197	2.629	289	1.605	381	0.539	473	0.595	565	0.183
14	4.610	106	3.617	198	2.618	290	1.594	382	0.527	474	0.608	566	0.184
														15	4.599	107	3.607	199	2.607	291	1.583	383	0.515	475	0.620	567	0.186
16	4.588	108	3.596	200	2.596	292	1.571	384	0.503	476	0.633	568	0.187
														17	4.577	109	3.585	201	2.585	293	1.560	385	0.491	477	0.646	569	0.188
18	4.567	110	3.574	202	2.574	294	1.549	386	0.479	478	0.659	570	0.190
														19	4.556	111	3.563	203	2.563	295	1.537	387	0.467	479	0.672	571	0.191
20	4.545	112	3.553	204	2.552	296	1.526	388	0.455	480	0.685	572	0.193
														21	4.534	113	3.542	205	2.541	297	1.515	389	0.443	481	0.698	573	0.194
22	4.523	114	3.531	206	2.530	298	1.503	390	0.431	482	0.710	574	0.195
														23	4.513	115	3.520	207	2.519	299	1.492	391	0.419	483	0.723	575	0.197
24	4.502	116	3.509	208	2.508	300	1.480	392	0.407	484	0.736	576	0.198
														25	4.491	117	3.499	209	2.497	301	1.469	393	0.395	485	0.749	577	0.200
26	4.480	118	3.488	210	2.486	302	1.458	394	0.383	486	0.762	578	0.201
														27	4.469	119	3.477	211	2.475	303	1.446	395	0.371	487	0.775	579	0.203

28	4.459	120	3.466	212	2.464	304	1.435	396	0.359	488	0.788	580	0.204
														29	4.448	121	3.455	213	2.453	305	1.424	397	0.347	489	0.801	581	0.205
30	4.437	122	3.444	214	2.442	306	1.412	398	0.335	490	0.814	582	0.207
														31	4.426	123	3.434	215	2.431	307	1.401	399	0.323	491	0.827	583	0.208
32	4.415	124	3.423	216	2.420	308	1.389	400	0.311	492	0.840	584	0.210
														33	4.405	125	3.412	217	2.409	309	1.378	401	0.299	493	0.853	585	0.211
34	4.394	126	3.401	218	2.398	310	1.366	402	0.287	494	0.866	586	0.213
														35	4.383	127	3.390	219	2.387	311	1.355	403	0.275	495	0.879	587	0.214
36	4.372	128	3.380	220	2.376	312	1.344	404	0.263	496	0.892	588	0.216
														37	4.362	129	3.369	221	2.365	313	1.332	405	0.251	497	0.905	589	0.217
38	4.351	130	3.358	222	2.354	314	1.321	406	0.239	498	0.918	590	0.218
														39	4.340	131	3.347	223	2.343	315	1.309	407	0.226	499	0.931	591	0.220
40	4.329	132	3.336	224	2.332	316	1.298	408	0.214	500	0.945	592	0.221
														41	4.318	133	3.325	225	2.321	317	1.286	409	0.202	501	0.958	593	0.223
42	4.308	134	3.315	226	2.310	318	1.275	410	0.190	502	0.971	594	0.224
														43	4.297	135	3.304	227	2.298	319	1.263	411	0.178	503	0.984	595	0.226
44	4.286	136	3.293	228	2.287	320	1.252	412	0.166	504	0.997	596	0.227
														45	4.275	137	3.282	229	2.276	321	1.240	413	0.154	505	0.101	597	0.229
46	4.264	138	3.271	230	2.265	322	1.229	414	0.141	506	0.102	598	0.230
														47	4.254	139	3.260	231	2.254	323	1.217	415	0.129	507	0.104	599	0.232
48	4.243	140	3.250	232	2.243	324	1.206	416	0.117	508	0.105	600	0.233
														49	4.232	141	3.239	233	2.232	325	1.194	417	0.105	509	0.106	601	0.235
50	4.221	142	3.228	234	2.221	326	1.183	418	0.925	510	0.108	602	0.236
														51	4.211	143	3.217	235	2.210	327	1.171	419	0.803	511	0.109	603	0.237
52	4.200	144	3.206	236	2.199	328	1.160	420	0.681	512	0.110	604	0.239
														53	4.189	145	3.195	237	2.188	329	1.148	421	0.558	513	0.112	605	0.240
54	4.178	146	3.185	238	2.177	330	1.137	422	0.436	514	0.113	606	0.242
														55	4.167	147	3.174	239	2.166	331	1.125	423	0.313	515	0.114	607	0.243
56	4.157	148	3.163	240	2.154	332	1.114	424	0.190	516	0.116	608	0.245
														57	4.146	149	3.152	241	2.143	333	1.102	425	0.067	517	0.117	609	0.246
58	4.135	150	3.141	242	2.132	334	1.090	426	0.056	518	0.118	610	0.248
														59	4.124	151	3.130	243	2.121	335	1.079	427	0.179	519	0.120	611	0.249
60	4.113	152	3.119	244	2.110	336	1.067	428	0.302	520	0.121	612	0.251
														61	4.103	153	3.109	245	2.099	337	1.056	429	0.425	521	0.122	613	0.252
62	4.092	154	3.098	246	2.088	338	1.044	430	0.548	522	0.124	614	0.254
														63	4.081	155	3.087	247	2.077	339	1.032	431	0.672	523	0.125	615	0.255
64	4.070	156	3.076	248	2.065	340	1.021	432	0.795	524	0.126	616	0.257
														65	4.060	157	3.065	249	2.054	341	1.009	433	0.919	525	0.128	617	0.258
66	4.049	158	3.054	250	2.043	342	0.998	434	0.104	526	0.129	618	0.260
														67	4.038	159	3.043	251	2.032	343	0.986	435	0.117	527	0.130	619	0.261
68	4.027	160	3.033	252	2.021	344	0.974	436	0.129	528	0.132	620	0.263
														69	4.016	161	3.022	253	2.010	345	0.963	437	0.141	529	0.133	621	0.264
70	4.006	162	3.011	254	1.999	346	0.951	438	0.154	530	0.134	622	0.266
														71	3.995	163	3.000	255	1.987	347	0.939	439	0.166	531	0.136	623	0.267
72	3.984	164	2.989	256	1.976	348	0.928	440	0.179	532	0.137	624	0.269
														73	3.973	165	2.978	257	1.965	349	0.916	441	0.191	533	0.139	625	0.270
74	3.963	166	2.967	258	1.954	350	0.904	442	0.204	534	0.140	626	0.272
														75	3.952	167	2.956	259	1.943	351	0.893	443	0.216	535	0.141	627	0.273
76	3.941	168	2.945	260	1.932	352	0.881	444	0.229	536	0.143	628	0.275
														77	3.930	169	2.935	261	1.920	353	0.869	445	0.241	537	0.144	629	0.276
78	3.919	170	2.924	262	1.909	354	0.858	446	0.254	538	0.145	630	0.278
														79	3.909	171	2.913	263	1.898	355	0.846	447	0.266	539	0.147	631	0.280
80	3.898	172	2.902	264	1.887	356	0.834	448	0.279	540	0.148	632	0.281
														81	3.887	173	2.891	265	1.876	357	0.822	449	0.291	541	0.149	633	0.283
82	3.876	174	2.880	266	1.864	358	0.811	450	0.304	542	0.151	634	0.284
														83	3.866	175	2.869	267	1.853	359	0.799	451	0.316	543	0.152	635	0.286
84	3.855	176	2.858	268	1.842	360	0.787	452	0.329	544	0.154	636	0.287
														85	3.844	177	2.847	269	1.831	361	0.775	453	0.341	545	0.155	637	0.289
86	3.833	178	2.836	270	1.820	362	0.764	454	0.354	546	0.156	638	0.290
														87	3.822	179	2.826	271	1.808	363	0.752	455	0.366	547	0.158	639	0.292
88	3.812	180	2.815	272	1.797	364	0.740	456	0.379	548	0.159	640	0.293
														89	3.801	181	2.804	273	1.786	365	0.728	457	0.3916	549	0.1604
90	3.790	182	2.793	274	1.775	366	0.717	458	0.4042	550	0.1618
														91	3.779	183	2.782	275	1.763	367	0.705	459	0.4168	551	0.1631
92	3.768	184	2.771	276	1.752	368	0.693	460	0.4295	552	0.1645

The point of error minimum is the 426km place, therefore thinks that the trouble spot is positioned at 426km.Calculating the fault localization relative error is:

$\frac{426-420}{800}\×100\%=0.75\%$

Use the inventive method and the fault localization error characteristics of using traditional power frequency impedance method for comparing check, the present invention is based on model shown in Figure 1 and carried out a large amount of Digital Simulations, the trouble spot is selected to be decremented to 10km gradually from 600km, and step-length is 10km; The fault transition resistance is since 5 ohm, with 50 ohm be step-length, increase to 155 ohm gradually.Simulation result as shown in Figure 2.

By Fig. 2 (a) as seen, the fault localization error characteristics of using traditional power frequency impedance method are very poor, even under the less situation of transition resistance (5 ohm, 55 ohm), the fault localization maximum relative error also can reach 30%; Along with the further increase of transition resistance value, the fault localization relative error reaches more than 50%, and the range finding result does not have credibility.

The fault localization error characteristics that adopt the inventive method are shown in Fig. 2 (b), and under the situation of little transition resistance, the fault localization maximum relative error is no more than 0.75%, realize precision ranging; Under the situation of great transition resistance, the precision of fault localization descends to some extent, but maximum relative error can satisfy the requirement of rig-site utilization less than 1.5%.

Claims (1)

1, the line one-end fault ranging method of a kind of anti-capacitance current and transition resistance influence may further comprise the steps:

1) measuring circuit is in transforming plant protecting installation place fault phase voltage phasor

Fault phase current phasor

The residual voltage phasor

The zero-sequence current phasor

The negative-sequence current phasor

As input quantity; Wherein

For fault separate: A phase, B are mutually or the C phase;

2) calculating the fault point voltage zero crossing is constantly:

Wherein α is the initial phase angle of route protection installation place negative-sequence current, and ω is the specified angular frequency value of electric system;

3) calculate the fault point voltage zero crossing constantly, the real part measured value of protection installation place measuring voltage is:

Measuring voltage

Wherein: U _RelayBe the measuring voltage amplitude, θ is the initial phase angle of measuring voltage; The fault point voltage zero crossing moment, the real part measured value of measuring voltage: U _{Mea_meter}=U _RelayCos (90 °-α+θ)

4) fault distance is taken as initial value l _Fault, calculate the protection installation place and measure electric current:

Measure electric current

Wherein: I _RelayFor measuring current amplitude, β is for measuring the initial phase angle of electric current;

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

P is the zero sequence current compensation factor based on the circuit distribution parameter, 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: ${\stackrel{\·}{\mathrm{\γ}}}_0=\sqrt{(R_0+\mathrm{j\ω}{L}_0)/(G_0+\mathrm{j\ω}{C}_0)};$

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

5) according to Transmission Line Distributed Parameter computational scheme resistance value Z _FaultFor:

$Z_{\mathrm{fault}}=Z_{c1}\mathrm{th}{\stackrel{\·}{\mathrm{\γ}}}_1{l}_{\mathrm{fault}}=Z_{\mathrm{relay}}(\cos (\mathrm{\ωt}+\mathrm{\τ})+j\sin (\mathrm{\ωt}+\mathrm{\τ}))$

Wherein: Z _RelayBe the line impedance amplitude, τ is the line impedance angle;

6) according to the fault point voltage zero crossing constantly, the real part calculated value of protection installation place measurement electric current and line impedance value calculating measuring voltage is:

U _{mea_cal}＝I _relayZ _relaycos(90°-α+τ+β)

7) calculating the real part calculated value of measuring voltage and the error of measured value is:

Error＝|U _{mea_cal}-U _{mea_meter}|

8) fault distance initial value l _FaultS increases one by one with step delta; return step 4); calculate the error amount of every bit successively; setting range until the protection of sending out trip signal; if can't be protected trip signal; then search for the protected circuit total length, the point of getting the error minimum is the trouble spot, and the distance of this trouble spot to route protection installation place is a fault distance.

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