Patent RU-2508555-C1 (RU)
Inventor: KHRUSHCHEV JURIJ VASIL EVICH
IPC: G01R27/04
Filed: 2012-10-05
Granted: 2014-02-27
Abstract: FIELD: electricity. 
     SUBSTANCE: method is based on electric network monitoring. It is distinguished by measurement of array of instantaneous values of signals of voltage and current of three phases in the beginning          u     A   1         (       t   j       )       |       N     j   =   1       ,             u     B   1         (       t   j       )       |       N     j   =   1       ,                 u     C   1         (       t   j       )       |       N     j   =   1       ,                     i     A   1         (       t   j       )       |       N     j   =   1       ,                     i     B   1         (       t   j       )       |       N     j   =   1       ,                     i     C   1         (       t   j       )       |       N     j   =   1             
 and in the end          u     A   2         (       t   j       )       |       N     j   =   1       ,                 u     B   2         (       t   j       )       |       N     j   =   1       ,                     u     C   2         (       t   j       )       |       N     j   =   1       ,                     i     A   2         (       t   j       )       |       N     j   =   1       ,                     i     B   2         (       t   j       )       |       N     j   =   1       ,                         i     C   2         (       t   j       )       |       N     j   =   1             
 of the line for the same moments of time t j =t 1 , t 2 , …t N  with discretion of array of instantaneous values        Δ   t   =     T   N     ,         
 where T is voltage/current period signal, N is partition number on the period T, signals are transferred from the end of the line to its beginning by communication channel, pairs of digital readout are stored as current, analogous signals of B and C phases are shifted to angles of 120° and 240° correspondingly, then simultaneously determined are arrays of instantaneous values of symmetrical components of voltage and current of direct and reverse sequences of A phase in the beginning and in the end of the line and corresponding vector values  U   Al,1 ,  I   A1,1 ,  U   A2,1 ,  I   A2,1 ,  U   A1,2 ,  I   A1,2 ,  U   A2,2 ,  I   A2,2 , then distance from place of I 1  phase loss is determined by expression:          l   1     =     1           γ   _       0         a   r   t   h     (               U   _         A   1,1       −         U   _         A   2,1       −     (           U   _         A   1,2       −         U   _         A   2,2         )     c   h     (           γ   _       0     L     )     −     (           I   _         A   1,2       −         I   _         A   2,2         )           Z   _       B     s   h     (           γ   _       0     L     )           (           I   _         A   1,1       −         I   _         A   2,1         )           Z   _       B     −     (           U   _         A   1,2       −         U   _         A   2,2         )     s   h     (           γ   _       0     L     )     −     (           I   _         A   1,2       −         I   _         A   2,2         )           Z   _       B     c   h     (           γ   _       0     L     )           )     ,         
 where  γ   0 =α 0 +jβ 0  is electromagnetic wave propagation coefficient; α 0  is electromagnetic wave damping coefficient; β 0  is electromagnetic wave phase-change coefficient;  Z   B  is line wave resistance; L is line length. 
     EFFECT: improving accuracy of determination of short-circuit place. 
     9 tbl, 2 dwg