The invention discloses a fault distance detection method for an active power distribution network, and the method comprises the following steps: first, obtaining the data of an active power distribution network; second, determining each power supply section so as to confirm the troubled section; using the forward-backward sweep method to calculate the injection current of the downstream of the troubled point to the troubled point; calculating the voltage phase amount and the current phase amount at the downstream end of the troubled section and calculating the nominal position of the troubled point; and finally calculating the distance from the troubled point to a transformer substation. In the method of the invention, the distribution-type power supply multi-point accessing is considered, and only through the use of the local voltage and current phase amounts and the synchronous current phase amount of the distribution-type power supply, it is possible to realize the fault distance detection for the active power distribution network. In addition, through the comparison of the current at the two sections of an area section, the positioning of a troubled area section can be realized. Through the calculation of the fault current and the contribution of the downstream current of the fault point to the fault current, the positioning and distance detection for the fault can be realized, making the method suitable for the fault distance detection under the condition of a multi-point distribution-type power supply accessing.

Fault distance detection method for active power distribution network

The invention discloses a single-end fault range finding method for a DC distribution line considering cable distribution capacitance The method comprises steps that S1, a fault range finding model taking cable distribution capacitance into account is established, and a fault range finding equation and a constant coefficient formula under the condition of considering the cable distribution capacitance are derived; S2, the rectifier side positive voltage and the rectifier side positive current after the fault are collected and substituted into the constant coefficient formula to obtain multiple sets of coefficients, and the multiple sets of coefficients are substituted into the fault range ranging equation to form an overdetermined equation group; and S3, the least squares method is utilized to solve the above overdetermined equations to obtain the fault distance x and the transition resistance Rf The method is advantaged in that aiming at problems existing in current DC distributionline fault range finding, the fault range finding equation considering cable distribution capacitance is derived, the parameters are identified through the least squares method, and the low-cost high-precision fault range finding method is provided for DC power distribution systems

Single-end fault range finding method for DC distribution line considering cable distribution capacitance

The invention provides a fault location method suitable for a tree power distribution network including distributed power supplies, belongs to the field of power distribution network relay protection,and solves the problems that multiple branches in the DG-included tree power distribution network and the DG power flow uncertainty influence the location result. The method comprises the following steps that firstly the data of the tree power distribution network including the distributed power supplies are acquired; then a positive sequence fault component network is analyzed, the voltage source is converted into the equivalent current source, the fault point injection current replaces the fault resistance branch, and the fault point injection current is displaced to the adjacent node of the fault branch by using the start network transformation method equivalent fault branch; then a fault location model is constructed based on the node voltage equation of the positive sequence fault component equivalent network; and finally all the branches are traversed, and the fault branch and the fault distance are determined according to the features of the solution of the equation. The methodis easy to implement and high in location accuracy without the influence of the access capacity and number of the distributed power supplies, the fault point position, the fault resistance or the fault type and has no location false root.

Fault location method suitable for tree power distribution network including distributed power supplies

The invention discloses a fault positioning method of an inverter-interfaced-distributed-generator-accessed distribution network. A voltage and a current of a head end of a feeder line as well as a voltage measuring value of a distributed-generator grid-connected point are introduced into a universal fault positioning equation, thereby carrying out rough fault positioning on a distributed network; and for the distributed network in fault states of all possible fault points, a loop current equation is established and is solved to obtain a head end voltage of the feeder line of the distributed network, and a fault point corresponding to a result closest to a practical measuring result is used as a precise fault point. Therefore, the fault positioning precision is high; and the fault positioning result is not affected by a fault type.

Fault positioning method of inverter-interfaced-distributed-generator-accessed distribution network

The present invention relates to the technical field of automation of power systems, and more particularly to a method for screening the optimal cable layout of double-circuit transmission lines. Themethod is characterized in that: through the Multiple Run module on the PSCAD/EMTDC simulation platform, the screening process with multiple arrangement manners is automated; in consideration of multiple line layout factors that affect the symmetry of cable layout parameters, the cable layout method that minimizes the unbalance of the three-phase line is quickly screened, so that the problem of the unbalance of three-phase line parameters caused by the cable line layout can be solved, and the safety of power system operation can be improved; and the method can increase the screening efficiency and save the screening time, has the characteristics of economical reliability, simple implementation and excellent performance, and can be applied to the actual engineering of double-circuit transmission lines.

Method for screening optimal cable layout of double-circuit transmission lines

The invention discloses an improved impedance type active distribution network fault location algorithm based on phasor analysis, belonging to the technical field of safe and stable operation of power systems. A one-variable quadratic ranging equation of distance-to-fault applicable to all kinds of fault types is built based on synchronous detection data of FTU devices at power access points before a fault and according to the fact that a transition resistor at a fault point consumes zero reactive power. The synchronous detection data is substituted into a forward-backward sweep power flow program containing distributed generation, load iteration calculation is performed to get the actual load power, fault location of a three-phase unbalanced active distribution network under various fault types is realized without pre-judging the fault type and faulty phase, the distance x(total) from an actual fault point to a main grid is calculated, and the searching and ranging process ends. The algorithm needs no pre-judgment on the fault type and faulty phase, and is of high ranging accuracy. The active distribution network fault location algorithm put forward by the invention has high ranging accuracy and good robustness.

Wang Xu

Papers

Improved impedance type active distribution network fault location algorithm based on phasor analysis