Process and system for the determination of a longitudinal equivalent reactance in an electric power supply line

A process for the determination of a longitudinal equivalent reactance in an electric power supply line with reference to a measuring point, particularly at the connecting point of a generator in a supply line, comprising:

• forming at the measuring point (x.sub.m), measuring signals for the system voltage (V.sub.1), real power (P) and apparent power (Q) as well as for the phase angle (d.sub.m) of the system voltage (V.sub.1) relative to a local reference (V.sub.r);
• forming a plurality of values (X.sub.e1, X.sub.e2, X.sub.e3) of the equivalent reactance to be determined in advance and determining a pertinent phase angle difference of the system voltage (d.sub.1 to d.sub.3) for each of these values with the help of the measuring signals for system voltage (V.sub.1), real and apparent power (P or Q, respectively);
• comparing the course of each phase angle difference of the system voltage (d.sub.1 to d.sub.3) with that of the phase angle (d.sub.m) of the power voltage (V.sub.1) at the measuring point (x.sub.m) and forming respective correlation characteristics (K.sub.1 to K.sub.3) based thereon;
• subjecting the correlation characteristics (K.sub.1 to K.sub.3) to a limit value selection wherein that phase angle difference of the system (d.sub.1 to d.sub.3) which is closest in similarity to the phase angle (d.sub.m) of the system voltage (V.sub.1) is identified;
• outputting the respective equivalent reactance value (X.sub.e1, X.sub.e2, X.sub.e3) associated with the phase angle difference of the system (d.sub.1 to d.sub.3) identified as being closest in similarity to the phase angle (d.sub.m) of the system voltage (V.sub.1).