CN204761043U - Grid system who contains loop network - Google Patents

Abstract

The utility model discloses a grid system who contains loop network. This system includes many generating set, many generating lines, many transmission line and trouble record ripples unit, and these many generating set are connected to different generating lines respectively, and partial generating line is connected through some transmission line and is formed loop network, this trouble record ripples unit includes fault oscillograph, connection and measuring device, wherein this measuring device sets up in each transmission line's both ends, and this measuring device is connected to the one end of this connection, and this fault oscillograph is connected to the other end of this connection. The utility model discloses grid system who contains loop network can carry out trouble selection automatically to be guaranteed the trouble abreast and selects the accuracy nature and the commonality of looks, and the hardware cost is low, the location is reliable.

Description

Network system containing loop network

Technical field

The utility model relates to power domain, is specifically related to a kind of network system containing loop network.

Background technology

Along with national economy develops rapidly, social need for electricity constantly increases, and various fault occurs ultra-high-tension power transmission line unavoidably, and this brings serious harm and impact to the normal operation of whole electric power system and reliable power supply.So research ultra-high-tension power transmission line Fault Phase Selection is particularly important.When electric power system is broken down, Novel Faulty Phase Selector accurately can identify fault type and to guarantee protective relaying device effective action, optionally excising fault phase has important meaning.

Impedance method is not considering in line mutual-ground capacitor and conductance situation, and voltage, the magnitude of current of utilization measurement are obtained the resistance value in fault loop thus realize Fault Phase Selection.Impedance method can be divided into again single-ended method and both-end method two kinds.Wherein, single-ended method principle is simple, but can not eliminate transition resistance and peer-to-peer system impedance variation and cause impact on positioning precision; It is large that both-end method compares single-ended method information needed amount, still also exists due to the position error that both-end sample frequency is inconsistent and phase deviation causes, therefore also there is limitation in actual applications.

Impedance method, mainly for the Fault Phase Selection of Radiation circuit, does not consider the practical structures of electrical network.Because the transmission line majority in high-voltage fence runs in loop network mode, method that is single-ended or both end information localize short circuits fault point is therefore utilized to be difficult to adapt to ring-like network structure.

Traveling wave method locating speed is fast, and precision is high, not by the impact of transition resistance, circuit types and system operation mode; But its significant shortcoming is that phase selection result is unreliable, and there is hardware high cost problem.

Utility model content

The purpose of this utility model is to provide a kind of network system containing loop network, plays a part automatically to carry out Fault Phase Selection and the accuracy ensureing Fault Phase Selection.

For achieving the above object, the utility model provides a kind of network system containing loop network, described network system comprises multiple stage generating set, many buses, many transmission lines and failure wave-recording unit, described multiple stage generating set is connected respectively to different buses, and part bus is connected to form loop network by part transmission line; Described failure wave-recording unit comprises fault oscillograph, connection and measurement mechanism; Wherein said measurement mechanism is arranged at the two ends of each transmission line, and one end of described connection connects described measurement mechanism, and the other end of described connection connects described fault oscillograph; And described fault oscillograph is provided with the circuit judging maximum transient voltage and the circuit judging maximum transient electric current.

Preferably, described network system comprises 3 generating sets, 8 buses, 7 transmission lines and 14 measurement mechanisms, and wherein, 4 buses are connected to form tetracyclic ring l network.

Preferably, described network system comprises 4 generating sets, 8 buses, 10 transmission lines and 20 measurement mechanisms, and wherein, 4 buses are connected to form tetracyclic ring l network.

Preferably, described multiple measurement mechanism comprises current transformer and voltage transformer.

Preferably, described network system also comprises multiple stage transformer, and each generating set is connected with a transformer.

Network system containing loop network of the present utility model automatically can be carried out Fault Phase Selection and ensure accuracy and the versatility of Fault Phase Selection, and hardware cost is low, location reliable.

Accompanying drawing explanation

Fig. 1 is electric power system schematic diagram of the present utility model.

Fig. 2 is fault phase equivalent circuit diagram.

Fig. 3 is the network system schematic diagram containing triangle loop network.

Fig. 4 is the connection diagram of failure wave-recording unit.

Fig. 5 is the structural representation of fault oscillograph.

Fig. 6 is the three dynamo-electric net system schematic of the utility model the present embodiment 3.

Fig. 7 is four dynamo-electric net system schematic of the utility model embodiment 4.

Fig. 8 is measuring point C ₁, C ₃, C ₈transient voltage curve.

Fig. 9 is measuring point C ₄, C ₆, C ₁₂transient voltage curve.

Figure 10 is measuring point C ₁~ C ₄current disturbing discharge curve.

Figure 11 is measuring point C ₅~ C ₈transient current curve.

Figure 12 is measuring point C ₉~ C ₁₂transient current curve.

Embodiment

Below with reference to accompanying drawing, preferred embodiment of the present utility model is described in detail, understands the purpose of this utility model, feature and advantage so that clearer.It should be understood that embodiment shown in the drawings is not the restriction to the utility model scope, and the connotation just in order to technical solutions of the utility model are described.

Term explanation

Transient state component: during system network architecture change, the energy-storage travelling wave tube such as inductance, electric capacity in network and the electric parameters that produces; It is decayed with exponential law, no longer exists after transient process terminates.

Fault Phase Selection: when transmission line breaks down, protective device, except measuring except fault distance, can also select out of order separate, i.e. Fault Phase Selection.

Current transformer (CT): it is made up of the iron core closed and winding, its effect primary current larger for numerical value can be converted to the less secondary current of numerical value by certain no-load voltage ratio, is used for carrying out protecting, the purposes such as measurement.If no-load voltage ratio is the current transformer of 400/5, the current transitions that can be 400A reality is the electric current of 5A.

Voltage transformer (PT): it is the transformer of band iron core, and its effect is that ac high voltage is changed into low-voltage, i.e. 100V, and voltage transformer primary side is connected on primary system, secondary side joint measuring instrument, relaying protection etc.

Generating set (G): be by the electric equipment that can be converted into electric energy of other form.

Transformer (T): utilize electromagnetic induction principle, is transformed to the device of the AC energy of the another kind of voltage of same frequency by a kind of AC energy of voltage.

Bus (M): in the voltage power distribution equipments at different levels of power plant and electric substation, refer to wire generator, transformer and various electric equipment coupled together, play the effect collecting and distribute electric energy.

Transmission line (L): refer to be located on shaft tower with insulator and corresponding gold utensil by wire and overhead ground wire suspension frame, connects power plant and transformer station, to realize the electric power facility for the purpose of transmission of electric energy.Primarily of compositions such as wire, overhead transmission line, insulator, gold utensil, shaft towers.

Measuring point: the position of measuring voltage and electric current.

Below in conjunction with Fig. 1, Fig. 2 and Fig. 3, the utility model is described.

Fig. 1 is electric power system schematic diagram of the present utility model, wherein M ₁, M ₂and M ₃for bus, G ₁, G ₂for generating set, bus M ₁, M ₂and M ₃all connected by transmission line, suppose when t=0s, bus M ₂, M ₃between circuit on there is three phase short circuit fault.

Fig. 2 is fault phase equivalent circuit diagram.After transmission line malfunction, be equivalent at the additional trouble power of fault point.Wherein, trouble power is equal with the voltage swing at this some place under normal circumstances, direction is contrary.If do not consider the impact of line mutual-ground capacitor and transition resistance, the equivalent circuit diagram of a certain fault phase as shown in Figure 2.

Suppose at t=0s moment short dot voltage expression be under normal operating conditions

u(t)＝-U _msin(ωt+α)(1)

Total differential equation is write, shown in (2) to left loop row:

$R_{1}di+L_1\frac{d\left(di\right)}{dt}=-U_{m}sin(\mathrm{\ω}t+\mathrm{\α})---\left(2\right)$

The solution of formula (2) is

Wherein

$I_m=\frac{U_m}{\sqrt[2]{{\mathrm{\ω}}^2{L}_1^2+R_1^2}};$ $\mathrm{\τ}=\frac{L_1}{R_1}$

As can be seen from formula (3), during short trouble, in transient state component, be surrounded by abundant attenuating dc component.The utility model definition voltage difference k is circuit L _mnthe transient voltage amount du of two ends measuring point _mand du _ndifference, expression formula is such as formula shown in (4):

k＝du _m-du _n(4)

As can be seen from formula (4), as k>0, electric current flows through node N by node M; Otherwise as k ﹤ 0, electric current flows through node N by node M.

When be short-circuited in electrical network fault time, the distortion that the transient state component produced in fault point will make the voltage at diverse location place, electric current occur in various degree.This is because in fault component network, only there is fault point power supply independent role, the peak value of fault point transient voltage is maximum.

Fig. 3 is the network system schematic diagram containing triangle loop network.In figure 3, if the direction that bus points to transmission line is the positive direction of electric current, and hypothesis transmission line L ₂₃be short-circuited fault.

Each measuring point C is extracted by each measurement mechanism ₁~ C ₁₂transient voltage, electric current, due to loop network break down time, from fault point more close to local voltage larger, measuring point C ₂, C ₃, C ₇or measuring point C ₄, C ₅, C ₉the peak value of the transient voltage curve extracted is maximum.

Present hypothesis measuring point C ₃maximum (the measuring point C of transient voltage extracted ₂, C ₇, C ₄, C ₅, C ₉with measuring point C ₃analytical method the same), then circuit L ₁₂, L ₂₃and L ₂₅it is possible faulty line.

The voltage difference calculated will meet k ₂₁>0, k ₇₈>0, illustrates circuit L ₁₂upper electric current di ₁₂by M ₂flow through M ₁, circuit L ₂₅upper electric current di ₂₅by M ₂flow through M ₅.Due to circuit L ₂₃be short-circuited fault, therefore faulty line L ₂₃electric current di on left side _f3m is flowed through by fault point ₂.Can be obtained by Kirchhoff's current law (KCL) (KCL)

di ₁₂+di ₂₅＝di _f3(5)

Can be obtained by formula (5), measuring point C ₃the peak value extracting transient current discharge curve must be greater than measuring point C ₂and C ₇extract the peak value of our transient current curve, so transmission line L can be judged ₂₃it is faulty line.

Based on above-mentioned analysis, below in conjunction with accompanying drawing, the utility model is described in detail.

The utility model relates to a kind of network system containing loop network, and this network system comprises multiple stage generating set, many buses, many transmission lines, multiple measurement mechanism and fault oscillographs; Wherein multiple stage generating set is connected respectively to different buses, and part bus is connected to form annular electrical network by part transmission line, and arranges a measurement mechanism in the end of each transmission line; And fault oscillograph is electrically connected with multiple measurement mechanism respectively by connection, multiple measurement mechanism detects instantaneous voltage on the transmission line of its position and transient current respectively, and this instantaneous voltage and transient current are passed to fault oscillograph.

Embodiment 1

Below in conjunction with Fig. 3, Fig. 4, Fig. 5, embodiment 1 of the present utility model is described.

Fig. 3 is the network system schematic diagram comprising triangle loop network of the utility model embodiment 1.As shown in Figure 3, the network system (hereinafter referred network system) comprising triangle loop network comprises two generating set G ₁, G ₂, two transformer T ₁, T ₂, 6 bus M ₁~ M ₆, 6 transmission line L ₁₂, L ₂₃, L ₃₄, L ₂₅, L ₃₅, L ₅₆, and failure wave-recording unit (as shown in Figure 4).

Wherein, all arrange measuring point at the two ends of each power transmission line circuit, 6 transmission lines arrange altogether 12 measuring point C ₁~ C ₁₂, be specially measuring point C ₁with measuring point C ₂lay respectively at transmission line L ₁₂two ends, namely near bus M ₁one end measuring point C is set ₁, near bus M ₂one end measuring point C is set ₂, measuring point C ₃with measuring point C ₄be arranged at transmission line L respectively ₂₃two ends, namely near bus M ₂one end measuring point C is set ₃, near bus M ₃one end measuring point C is set ₄, measuring point C ₅with measuring point C ₆be arranged at transmission line L respectively ₃₄two ends, namely near bus M ₃one end measuring point C is set ₅, near bus M ₄one end measuring point C is set ₆, measuring point C ₇with measuring point C ₈be arranged at transmission line L respectively ₂₅two ends, namely near bus M ₂one end measuring point C is set ₇, near bus M ₅one end measuring point C is set ₈, measuring point C ₉with measuring point C ₁₀be arranged at transmission line L respectively ₃₅two ends, namely near bus M ₃one end measuring point C is set ₉, near bus M ₅one end measuring point C is set ₁₀, measuring point C ₁₁with measuring point C ₁₂be arranged at transmission line L respectively ₅₆two ends, namely near bus M ₅one end measuring point C is set ₁₁, near bus M ₆one end measuring point C is set ₁₂.

As shown in Figure 4, failure wave-recording unit comprises fault oscillograph, connection and 12 measurement mechanisms, wherein, 12 measurement mechanisms are formed by combining by current transformer (CT) and voltage transformer (PT), are respectively used to detection 12 measuring point C ₁~ C ₁₂transient voltage and transient current, current transformer (CT) be used for gather transient current, voltage transformer (PT) be used for gather transient voltage, and by connection with send this voltage and current to fault oscillograph.In the present embodiment, this connection is RS485 or optical fiber.

Generating set G ₁output be connected to transformer T ₁input, transformer T ₁output be connected to bus M ₁, bus M ₁by transmission line and bus M ₂electric connection, bus M ₂with bus M ₃electricity Federation leads to, generating set G ₂output and transformer T ₂input electric connection, transformer T ₂output be connected to bus M ₄, bus M ₄with bus M ₃by transmission line L ₃₄electric connection.Bus M ₂with bus M ₅by transmission line L ₂₅electric connection, bus M ₅with bus M ₃by transmission line L ₃₅electric connection, bus M ₆with bus M ₅by transmission line L ₅₆electric connection, thus bus M ₂, bus M ₃and bus M ₅by transmission line L ₂₃, L ₂₅and L ₃₅form triangle loop network.

Fig. 5 is the structural representation of fault oscillograph.As shown in Figure 5, fault oscillograph comprises analogue collection module, switching value isolation module, record ripple CPU module and MMI module.Wherein, analogue collection module is made up of little CT, little PT etc., and acquisition module gathers voltage, the current signal that connection passes over.Switching value isolation module is made up of Resistor-Capacitor Unit and photoisolator, realizes the isolated variable of on-off model.Record ripple CPU module for core, comprises DSP part and CPU part with high performance 32 embedded microprocessor systems and technical grade bus.DSP part completes the calculating of Hilbert transform and correlative, judges whether to start record ripple simultaneously, and the real time data gathered is sent to CPU, also receives the order of CPU simultaneously.CPU part carries out the data record of fault period, starts coherent signal relay and device surface partitioned signal lamp simultaneously.MMI module adopts embedded 32 bit processors, completes the functions such as stable state record ripple, failure wave-recording and monitoring in real time.Can there is moment interface display voltage, current waveform profile and residual voltage curve by record trouble in MMI module simultaneously.

In the present embodiment, when circuit malfunctions, measurement mechanism measures transient voltage and the transient current of each measuring point on each transmission line, and send fault oscillograph to by connection, fault oscillograph is provided with the circuit judging maximum transient voltage and the circuit judging maximum transient electric current, and performs following steps:

Judge the maximum transient voltage U in described transient voltage _max;

Judge that there is described maximum transient voltage U _maxmeasuring point C;

Judge the transmission line L at described measuring point C place;

Judge the bus M be connected with transmission line L _kwith bus M _k-1,, wherein, with bus M _kthe transmission line connected is L _1k, L _2k... L _mk, wherein m>=2, with bus M _k-1the transmission line connected is L _{1 (k-1)}, L _{2 (k-1)}... L _{n (k-1)}, wherein n>=2;

Detect transmission line L _ikon close bus M _kthe transient current I of measuring point _ik, wherein (i=1,2 ... m);

Detect transmission line L _{j (k-1)}close bus M _k-1the transient current I of measuring point _{j (k-1)}, (j=1,2 ... n);

Judge described transient current I _ikwith described transient current I _{j (k-1)}in maximum transient electric current I _max;

Failure judgement circuit, has described maximum transient electric current I _maxtransmission line be faulty line.

Embodiment 2

Fig. 6 is the three dynamo-electric net system schematic of the present embodiment.The place do not described in detail is in the present embodiment identical with embodiment 1, refers to embodiment 1.

As shown in Figure 6, the network system (hereinafter referred network system) comprising tetracyclic ring l network comprises 3 generating set G ₁, G ₂, G ₃, 3 transformer T ₁, T ₂, T ₃, 8 bus M ₁~ M ₈, 8 transmission line L ₁₂, L ₂₇, L ₂₅, L ₃₅, L ₃₇, L ₃₄, L ₇₈and L ₅₆, and failure wave-recording unit (as shown in Figure 4).

Wherein, generating set G ₁output be connected to transformer T ₁input, transformer T ₁output be connected to bus M ₁, bus M ₁by transmission line and bus M ₂electric connection, generating set G ₂output and transformer T ₂input electric connection, transformer T ₂output be connected to bus M ₄, bus M ₄with bus M ₃by transmission line L ₃₄electric connection.Generating set G ₃output and transformer T ₃input electric connection, T ₃with output be connected to bus M ₈, bus M ₈with bus M ₇by transmission line L ₇₈electric connection.Bus M ₅with bus M ₆by transmission line L ₅₆electric connection, bus M ₅with bus M ₂by transmission line L ₂₅electric connection, bus M ₅with bus M ₃by transmission line L ₃₅electric connection, bus M ₂with bus M ₇by transmission line L ₂₇electric connection, bus M ₃with bus M ₇by transmission line L ₃₇electric connection, thus bus M ₂, bus M ₃, bus M ₅and bus M ₇by transmission line L ₂₅, L ₃₅, L ₃₇and L ₂₇form tetracyclic ring l network.

Wherein, at transmission line L ₁₂, L ₂₇, L ₂₅, L ₃₅, L ₃₇, L ₃₄, L ₇₈and L ₅₆the two ends of each transmission line two measuring point (not shown) are set respectively, 16 measuring points altogether.

As shown in Figure 4, failure wave-recording unit comprises fault oscillograph, connection and 16 measurement mechanisms, wherein, 16 measurement mechanisms are formed by combining by current transformer (CT) and voltage transformer (PT), are respectively used to detection 16 measuring point C ₁~ C ₁₂transient voltage and transient current, current transformer (CT) be used for gather transient current, voltage transformer (PT) be used for gather transient voltage, and by connection with send this voltage and current to fault oscillograph.In the present embodiment, this connection is RS485 or optical fiber.

Embodiment 3

Fig. 7 is the four dynamo-electric net system schematic of the present embodiment.The place do not described in detail is in the present embodiment identical with embodiment 2 with embodiment 1, refers to embodiment 1 and embodiment 2.

As shown in Figure 7, the four machine network systems (hereinafter referred four machine network system) comprising pentagon loop network comprise 4 generating set G ₁, G ₂, G ₄, G ₅, 4 transformer T ₁, T ₂, T ₄, T ₅, 8 bus M ₁~ M ₈, 10 transmission line L ₁₂, L ₂₇, L ₂₅, L ₃₄, L ₃₅, L ₅₇, L ₅₈, L ₃₈, L ₇₈and L ₅₆, 20 measurement mechanism (not shown), and failure wave-recording unit (as shown in Figure 4).

Wherein, generating set G ₁output be connected to transformer T ₁input, transformer T ₁output be connected to bus M ₁, bus M ₁by transmission line L ₁₂with bus M ₂electric connection, generating set G ₂output and transformer T ₂input electric connection, transformer T ₂output be connected to bus M ₄, bus M ₄with bus M ₃by transmission line L ₃₄electric connection.Generating set G ₄output and transformer T ₄input electric connection, T ₄output be connected to bus M ₇.Generating set G ₅output and transformer T ₅input electric connection, transformer T ₅output be connected to bus M ₈, bus M ₈with bus M ₇by transmission line L ₇₈electric connection.Bus M ₅with bus M ₆by transmission line L ₅₆electric connection, bus M ₅with bus M ₂by transmission line L ₂₅electric connection, bus M ₅with bus M ₃by transmission line L ₃₅electric connection, bus M ₂with bus M ₇by transmission line L ₂₇electric connection, bus M ₃with bus M ₈by transmission line L ₃₈electric connection, bus M ₅with bus M ₇by transmission line L ₅₇electric connection, bus M ₅with bus M ₈by transmission line L ₅₈electric connection, thus bus M ₂, bus M ₃, bus M ₅, bus M ₇and bus M ₈by transmission line L ₂₅, L ₃₅, L ₃₈, L ₇₈and L ₂₇form pentagon loop network.

Wherein, at transmission line L ₁₂, L ₂₇, L ₂₅, L ₃₅, L ₃₄, L ₅₇, L ₅₈, L ₃₈, L ₇₈and L ₅₆the two ends of each transmission line two measurement point (not shown) are set respectively, 20 measuring points altogether.

As shown in Figure 4, failure wave-recording unit comprises fault oscillograph, connection and 16 measurement mechanisms, wherein, 16 measurement mechanisms are formed by combining by current transformer (CT) and voltage transformer (PT), are respectively used to detection 16 measuring point C ₁~ C ₁₂transient voltage and transient current, current transformer (CT) be used for gather transient current, voltage transformer (PT) be used for gather transient voltage, and by connection with send this voltage and current to fault oscillograph.In the present embodiment, this connection is RS485 or optical fiber.

According to another aspect of the present utility model, additionally provide the method for Fault Phase Selection in a kind of high compression ring l network, high compression ring l network comprises multiple stage generating set, many buses, many transmission lines, wherein multiple stage generating set is connected respectively to different buses, and part bus is connected to form loop network by part transmission line.The method comprises the following steps:

Step one, measuring point is set in the end of each transmission line;

Step 2, detect the transient voltage of each measuring point;

Step 3, the maximum transient voltage U judged in transient voltage _max;

Step 4, judgement have maximum transient voltage U _maxmeasuring point C;

Step 5, judge the transmission line L at measuring point C place;

The bus M that step 6, judgement are connected with transmission line L _kwith bus M _k-1,, wherein, with bus M _kthe transmission line connected is L _1k, L _2k... L _mk, wherein m>=2, with bus M _k-1the transmission line connected is L _{1 (k-1)}, L _{2 (k-1)}... L _{n (k-1)}, wherein n>=2;

Step 6, detection transmission line L _ikon close bus M _kthe transient current I of measuring point _ik, wherein (i=1,2 ... m);

Step 7, detection transmission line L _{j (k-1)}on close bus M _k-1the transient current I of measuring point _{j (k-1)}, (j=1,2 ... n);

Step 8, judge transient current I _ikwith transient current I _{j (k-1)}in maximum transient electric current I _max;

Step 9, failure judgement circuit, have maximum transient electric current I _maxtransmission line be faulty line.

Particularly:

Step 2 is for detecting multiple transient voltage of measuring point described in each and drawing transient voltage curve;

Step 3 is judge the maximum in the peak value of described transient voltage curve, and described maximum is described maximum transient voltage U _max;

Step 6 is for detecting transmission line L _ikon close bus M _kmultiple transient current I of measuring point _ikand draw transient current curve,

Step 7 is for detecting transmission line L _{j (k-1)}close bus M _k-1multiple transient current I of measuring point _{j (k-1)}and draw transient current curve; And

Step 8 is for judge described transient current I _ikwith described transient current I _{j (k-1)}peak value in maximum transient electric current I _max.

Mode below by emulation verifies this method.

The first, use Simulink emulation to build simulation model with reference to the network system schematic diagram containing triangle loop network described in Fig. 3, transmission line chooses identical parameters model, and the length of each transmission line is as shown in the table.

Power transmission line	L 12	L 23	L 34	L 25	L 35	L 56
							Length	200	150	200	100	80	200

The second, suppose when t=0s, on transmission line L23, distance bus M2 holds 60km place that three phase short circuit fault occurs.

3rd, as illustrated in figs. 8-12, utilize Hilbert-Huang transform to carry out data processing to the voltage of all measuring points, current signal, obtain the transient voltage of different measuring points, magnitude of current curve respectively.Because the transient voltage discharge curve of some measuring point is identical, therefore the utility model only lists partial trace.

4th, can be found out by the transient voltage discharge curve in Fig. 8, measuring point C ₃the peak value of transient voltage line is maximum.Therefore, circuit L ₁₂, L ₂₃and L ₂₅it is possible faulty line.Again because as shown in Figure 10 ~ 12, measuring point C ₃the peak value extracting transient current curve is greater than measuring point C ₂and C ₇the peak value of transient current curve, so can judge transmission line L ₂₃it is possible faulty line.

5th, can be found out by the transient voltage discharge curve in Fig. 9, measuring point C ₄the peak value of transient voltage line is maximum.Therefore, circuit L ₂₃, L ₃₄and L ₃₅it is possible faulty line.Again because as shown in Figure 10 ~ 12, measuring point C ₄the peak value extracting transient current curve is greater than measuring point C ₅and C ₉the peak value of transient current curve, so can judge transmission line L ₂₃it is possible faulty line.

Comprehensive 5th and the 6th, transmission line L can be drawn ₂₃it is faulty line.

Judged result conforms to completely with real simulation situation.

Below described preferred embodiment of the present utility model in detail, but it will be appreciated that, after having read above-mentioned instruction content of the present utility model, those skilled in the art can make various changes or modifications the utility model.These equivalent form of values fall within the application's appended claims limited range equally.

Claims (5)

1. the network system containing loop network, it is characterized in that, described network system comprises multiple stage generating set, many buses, many transmission lines and failure wave-recording unit, described multiple stage generating set is connected respectively to different buses, and part bus is connected to form loop network by part transmission line; Described failure wave-recording unit comprises fault oscillograph, connection and measurement mechanism; Wherein said measurement mechanism is arranged at the two ends of each transmission line, and one end of described connection connects described measurement mechanism, and the other end of described connection connects described fault oscillograph; And described fault oscillograph is provided with the circuit judging maximum transient voltage and the circuit judging maximum transient electric current.

2. network system according to claim 1, is characterized in that, described network system comprises 3 generating sets, 8 buses, 7 transmission lines and 14 measurement mechanisms, and wherein, 4 buses are connected to form tetracyclic ring l network.

3. network system according to claim 1, is characterized in that, described network system comprises 4 generating sets, 8 buses, 10 transmission lines and 20 measurement mechanisms, and wherein, 4 buses are connected to form tetracyclic ring l network.

4. network system according to claim 1, is characterized in that, described multiple measurement mechanism comprises current transformer and voltage transformer.

5. network system according to claim 1, is characterized in that, described network system also comprises multiple stage transformer, and each generating set is connected with a transformer.