METHOD OF DETERMINING VALUE OF STATIONARY RESISTANCE OF EARTHING ARRANGEMENT OF SUPPORTS OF OVERHEAD POWER TRANSMISSION LINES WITHOUT DISCONNECTION OF OVERHEAD GROUND WIRE AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2020 - IPC G01R27/00 

FIELD: measurement.

SUBSTANCE: use to determine value of stationary resistance of earthing arrangement (EA) of overhead power transmission towers (OL) without disconnection of overhead ground wire and device for its implementation. Essence of the invention consists in that the method of determining the value of the stationary resistance of the earthing arrangement (EA) of overhead power transmission lines (OL) without disconnection of the overhead ground wire includes the impact on the EA of the support with a rectangular current pulse, recording values of current strength through EA i_j and voltage drop on EA u_j with respect to the remote potential electrode at discrete instants t_j, calculating the transient impedance EA z_j by the given formula and determining the equivalent active resistor replacement circuit EA R_EA, based on the obtained data array z_j on the measurement interval Δt_MES, calculation of stationary EA resistance of OL support R_LF by formula, taking into account wave resistance of overhead ground wires, suitable for support:

where n_GW is number of overhead ground wires, which are suitable to analyzed support, Z_WGW is value of wave resistance of overhead ground wire – ground surface, characterized by that at measurement interval Δt_MES, limited on one side by the current pulse start, and on the other side only by the arrival time of reflections from neighboring supports by overhead ground wires, performing exponential smoothing of a number of values z_j, considering that impedance EA includes capacitive component, smoothed dependence zs_j is described by expression:

where R_EA, C_EA – resistance and capacitance of equivalent R-L-C equivalent circuit of EA, determining equivalent active EA resistance of OL support R_EA as value of asymptote, to which dependence zs_j tends at the end of interval of measurement the Δt_MES, by formula:

where N is total number of discrete values of row zs_j on measurement interval Δt_MES, N_av is number of discrete values zs_j falling within limits of averaging interval Δt_av, the end of which coincides with the end of the measurement interval Δt_MES, and duration is 1/8 of duration Δt_MES, then stationary resistance EA R_LF is determined.

EFFECT: possibility of increasing accuracy of determining stationary resistance EA of OL supports without disconnection of overhead ground wire, including supports, EA of which have large area of earthing electrode and (or) are located in soil with high specific resistance, and information value of obtained data.

3 cl, 2 tbl, 7 dwg