CN102916406B - Self-adaption braking method for regional networked differential protection - Google Patents

Abstract

The invention relates to a self-adaption braking method for regional networked differential protection (DP). The method comprises the following steps: creating an association link table of each network node according to connection relationships of other network nodes in DP associated with each network node in a regional network; collecting status quantity information and analog quantity information transmitted by each breaker, and calculating a variable quantity of the current of each network node; selecting the network node with the maximum variable quantity of the current as a fault point if an abnormal variation of the current of the network node is detected; acquiring the number of the network nodes associated with the fault point in the association link tables of the network nodes, and adaptively performing main back-up protection on the fault point to select a braking equation according to the numerical value; and if the equation is met, performing protection actions and tripping associated breakers off. In the method, different braking equations and braking coefficients are selected for protected objects adaptively according to the number of the network nodes in the DP, thereby ensuring enough sensitivity in different situations. In addition, no person is needed to participate in setting.

Description

Regional Networked differential protection self adaptation braking method

Technical field

The invention belongs to Relay Protection Technology in Power System field, relate to a kind of self adaptation differential protection braking method being applied to the centralized protection of regional power grid.

Background technology

The current information of multiple measurement point can be obtained easily by high-performance, independently communication system in Regional Networked relaying protection system; can not only finished surface to the differential protection function of independent electrical element; the differential protection function towards the region be made up of multiple independent electrical element can also be realized, for electric power system provides the current differential protection of quick action, highly sensitive, function admirable.

Regional Networked protects main backup protection all to adopt Differential Protection Theory, and main protection Fault Isolation scope definition is all switches be directly connected with fault point, does multiterminal differential protection, all switches that during protection act, tripping is connected with fault point with these switches CT.Backup protection is defined as when the switch CT exception of in main protection isolation range or malfunctioning switch; multiterminal differential protection is carried out with the switch CT electric current of this exception of replacement with the CT electric current that other fault point is directly connected with all switch CT node currents that switch is directly connected therewith; during protection act except all switches that tripping is connected with fault point, also want all switches that tripping and CT exception or malfunctioning switch is directly connected.When multiple switch is abnormal, process equally.

Networking current differential protection principle is substantially the same with GPF (General Protection False; also be meet Kirchhoff's current law (KCL); difference is; the object of protection of conventional current differential protection is single electric component, and the object of protection of Regional Networked current differential protection is the region comprising multiple single electric component.Now not high about the general sensitivity of braking of Regional Networked differential protection, and need artificial participation to adjust.

Summary of the invention

The object of this invention is to provide a kind of Regional Networked differential protection self adaptation braking method, need people to be the problem of adjusting to solve compartmentalization network differential protection braking characteristic.

For achieving the above object, Regional Networked differential protection self adaptation braking method step of the present invention is as follows:

(1) annexation of other network nodes in the differential protection of Regional Networked differential protection associated by network node each in Local Area Network, sets up the association chained list of each network node;

(2) gather by the quantity of state information that each network node send and analog quantity information, and calculate each network node current change quantity;

(3) if certain network node electric current generation ANOMALOUS VARIATIONS detected, then the maximum network node of current anomaly variable quantity is chosen as fault point;

(4) obtain the number of network node that is associated with fault point in the association chained list of network node, and carry out main backup protection for fault point choose braking equation according to this numerical value is adaptive; Meet the equation then circuit breaker that is associated of protection act tripping.

Further, the differential protection in described step (1) associated by each network node comprises main protection and backup protection.

Further, the number of network node be associated with fault point in described step (4) comprises fault point itself, carries out main backup protection choose braking equation according to this numerical value is adaptive for fault point, and when numerical value is 2, braking equation is | I _{φ 1}+ I _{φ 2}| > k*|I _{φ 1}-I _{φ 2}|, wherein k=0.7, when numerical value is greater than 2, braking equation is wherein n be greater than 2 integer, k is the coefficient of ratio, I _{φ n}it is the current value of the network node that n-th is associated with fault point.

Further, described coefficient of ratio k adjusts according to the size adaptation of n, and when 2 < n≤5, k is 0.5, and when 5 < n≤12, k is 0.6, and as n > 12, k is 0.3.

Further, described network node is be connected into each branch road within the scope of regional power grid or the circuit breaker on branch road.

Regional Networked differential protection self adaptation braking method of the present invention first Sampling network node current ANOMALOUS VARIATIONS time, with the maximum network node of current change quantity for fault point, transfer the association chained list of this fault point, and the carrying out main backup protection for fault point and choose braking equation of the network node size adaptation associated according to this fault point; If meet equation, the circuit breaker that protection act tripping are associated; this method chooses different braking equations and restraint coefficient according to the quantity participating in differential protection network node is adaptive for protected object; ensure there is enough sensitivity in different situations, and do not need to think that participation is adjusted.

Accompanying drawing explanation

Fig. 1 is flow chart of the present invention;

Fig. 2 is system allocation plan of embodiment;

Fig. 3 be embodiment by the 1DL chained list schematic diagram of Topology g eneration.

Embodiment

The structure of regional power grid centralized network protection is by centralized protective device, communication network and install comprehensive intelligent unit on the spot and form, and regional power grid centralized network protection main protection adopts Differential Protection Theory, and backup protection adopts the differential protection in band time limit.As shown in Figure 1, concrete steps are as follows for Regional Networked differential protection self adaptation braking method:

(1) annexation of other network nodes in the differential protection of Regional Networked differential protection associated by network node each in Local Area Network, set up the association chained list of each network node, network node can for being connected into the circuit breaker on each branch road of bus or branch road, differential protection main protection and backup protection;

(2) gather quantity of state information and analog quantity information that each network node (circuit breaker) send, and calculate each network node current change quantity;

(3) if certain network node electric current generation ANOMALOUS VARIATIONS detected, then the maximum network node of current anomaly variable quantity is chosen as fault point;

(4) obtain the number of network node that is associated with fault point in the association chained list of network node, and carry out main backup protection for fault point choose braking equation according to this numerical value is adaptive; Meet the equation then circuit breaker that is associated of protection act tripping.

The number of network node be associated with fault point comprises fault point itself, carries out main backup protection choose braking equation according to this numerical value is adaptive for fault point, and when numerical value is 2, braking equation is | I _{φ 1}+ I _{φ 2}| > k*|I _{φ 1}-I _{φ 2}|, wherein k=0.7, when numerical value is greater than 2, braking equation is wherein n be greater than 2 integer, k is the coefficient of ratio, I _{φ n}it is the current value of the network node that n-th is associated with fault point.Coefficient of ratio k adjusts according to the size adaptation of n, and when 2 < n≤5, k is 0.5, and when 5 < n≤12, k is 0.6, and as n > 12, k is 0.3.

Below in conjunction with Fig. 2 and Fig. 3, Regional Networked differential protection self adaptation braking method is described in detail:

If Fig. 2 is the network diagram of primary system, Fig. 3 is the association chained list of the 1DL generated by topological structure.5 branch road L1 (doing differential containing 1DL, 8DL), L2 (2DL, 9DL), L3 (10DL, 3DL), B1 (4DL, 6DL, 7DL) and (1DL, 2DL, 5DL, 3DL, 4DL) can be divided into; The collection of the magnitude of current with each circuit breaker for collection point is carried out.L1 line failure in Fig. 2, first networking protective device selects L1 line failure, then dispatches the main protection of bus associated by the differential main protection of circuit L1 and 1DL.Drop into the calculating that formula 1 and formula 2 carry out differential main protection respectively, meet the equation then circuit breaker that is associated of protection act tripping.

$\left\{\begin{array}{c}{I}_d=|{\stackrel{\&CenterDot;}{I}}_{1\mathrm{DL}}+{\stackrel{\&CenterDot;}{I}}_{8\mathrm{DL}}|>I_{\mathrm{SET}}\\ I_d>K*I_r\end{array}\right.---\left(1\right)$

Wherein $\mathrm{Ir}=|{\stackrel{\&CenterDot;}{I}}_{1\mathrm{DL}}-{\stackrel{\&CenterDot;}{I}}_{8\mathrm{DL}}|,k=0.7.$

$\left\{\begin{array}{c}{I}_d=|{\stackrel{\&CenterDot;}{I}}_{1\mathrm{DL}}+{\stackrel{\&CenterDot;}{I}}_{2\mathrm{DL}}+{\stackrel{\&CenterDot;}{I}}_{5\mathrm{DL}}|>I_{\mathrm{SET}}\\ I_d>K*I_r\end{array}\right.---\left(2\right)$

Wherein $\mathrm{Ir}=\left|{\stackrel{\&CenterDot;}{I}}_{1\mathrm{DL}}\right|+\left|{\stackrel{\&CenterDot;}{I}}_{2\mathrm{DL}}\right|+\left|{\stackrel{\&CenterDot;}{I}}_{5\mathrm{DL}}\right|,k=0.5,$

The phasor difference of what the braking equation of formula 1 adopted is both sides electric current, and the braking equation of formula 2 adopts be multiterminal electric current absolute value and.If this is identifying that the length of 1DL chained list both sides is 2 (containing contacts own), using formula 1, if chained list length is greater than 2, then formula 2 is used to carry out.

When CT or the malfunctioning switch of main protection association, during as 5DL malfunctioning switch, need to utilize the adaptive increase protection range of topological structure, namely 1DL is adopted, 2DL, 3DL, the electric current of 4DL tetra-nodes completes differential backup protection, now need for different braking characteristics is chosen in the differential backup protection of networking, Regional Networked backup protection due to connected parts number more, the differential equation adopting formula 2 to carry out can cause sensitivity decrease, therefore the method according to how many self-adaptative adjustment ratio automatic coefficients participating in computing element is considered, as formula 3, shown in 4.

$\left\{\begin{array}{c}k=\mathrm{0.5,2}<n\&le;5\\ k=\mathrm{0.6,5}<n\&le;12\\ k=0.3,n>12\end{array}\right.---\left(4\right)$

Symbol implication in formula (1)-(4) and accompanying drawing:

I _dfor differential current, I _rfor stalling current, k is restraint coefficient, I _{φ n}for the electric current of fault branch n, n is the network node quantity be associated with fault point, and DL is circuit breaker, and B1 is transformer, and NULL indicates the link without next stage.

Claims (4)

1. a Regional Networked differential protection self adaptation braking method, is characterized in that, the step of the method is as follows:

(1) Regional Networked differential protection is according to the annexation of other network nodes in network node each in Local Area Network and associated differential protection, sets up the association chained list of each network node;

(2) gather the quantity of state information that each network node send and analog quantity information, and calculate each network node current change quantity;

(3) if detect, certain network node electric current changes, then choose the maximum network node of current change quantity as fault point;

(4) obtain the number of network node that is associated with fault point in the association chained list of network node, and carry out main backup protection for fault point choose braking equation according to this numerical value is adaptive; Meet the equation then circuit breaker that is associated of protection act tripping;

The number of network node be associated with fault point in described step (4) comprises fault point itself, carries out main backup protection choose braking equation according to this numerical value is adaptive for fault point, and when numerical value is 2, braking equation is | I _{φ 1}+ I _{φ 2}| > k*|I _{φ 1}-I _{φ 2}|, wherein k=0.7, when numerical value is greater than 2, braking equation is wherein n be greater than 2 integer, k is the coefficient of ratio, I _{φ n}it is the current value of the network node that n-th is associated with fault point.

2. Regional Networked differential protection self adaptation braking method according to claim 1, is characterized in that: the differential protection in described step (1) associated by each network node comprises main protection and backup protection.

3. Regional Networked differential protection self adaptation braking method according to claim 1; it is characterized in that; described coefficient of ratio k adjusts according to the size adaptation of n; when 2 < n≤5; k is 0.5, and when 5 < n≤12, k is 0.6; as n > 12, k is 0.3.

4. the Regional Networked differential protection self adaptation braking method according to any one of claim 1-3, is characterized in that, described network node is be connected into each branch road within the scope of regional power grid or the circuit breaker on branch road.