The application belongs to the technical field of
power grid power supply, and particularly relates to a measurement method and
system for
tower grounding resistance, which comprises the following steps: constructing a chain
linear network model, setting an
engineering typical value of the grounding impedance of each
tower, constructing a prior
admittance matrix, inverting the prior
admittance matrix to obtain a prior impedance matrix, injecting a mixed
excitation current signal with multiple different frequencies into the grounding lead of the measured
tower, synchronously collecting the measured
voltage of all nodes, separating the measured
voltage under each frequency, calculating an
admittance deviation matrix and an impedance
deviation matrix, establishing an approximate
linear relationship between the impedance
deviation matrix and the admittance deviation matrix and a
voltage difference vector, solving the approximate
linear relationship, obtaining the impedance deviation of the grounding impedance under each frequency relative to the
engineering typical value of the grounding impedance, calculating the actual grounding impedance, and separating the actual grounding impedance to obtain the
grounding resistance. The application realizes the inversion of the
grounding resistance from the external port measurement value without disassembling any grounding lead.