INPE 50 Nowe rozwiązania pomiaru impedancji pętli zwarciowej przy odkształceniu krzywej napięcia w miejscu badania

Zeszyt 50
Ryszard Roskosz
Nowe rozwiązania pomiaru impedancji pętli zwarciowej
przy odkształceniu krzywej napięcia w miejscu badania
Listopad 2014 2 Podręcznik

Autor: dr hab. inż. Ryszard Roskosz, prof. PG
Recenzenci: dr hab. in¿ Zdzisław Nawrocki, prof. PW,
prof. dr hab. inż. Jerzy Sawicki

ABSTRACT
This study is devoted to the problems of power system loop impedance measurement
in low voltage systems with special reference to cases where the voltage waveform
at the testing point is distorted. An analysis of the effect of waveform distortion
on measurement errors allows for the assessment of known loop impedance measuring
methods and instruments in networks with distinct voltage waveform distortion.
New patented solutions for loop impedance measurement, which eliminate the effect
of higher harmonics on the measurement result are proposed.
The significance of loop impedance measurements is presented in the introduction,
followed by an outline of the aim and scope of the dissertation. Problems of loop
impedance measurement in networks with sinusoidal voltage waveforms are discussed
in the leading chapters. The effect on measurement errors of factors like: difference
in phase angle between loop impedance and measurement load impedance,
network voltage fluctuations, presence of working loads, and the existence of transients
in the tested circuit due to operation of the measuring instrument, are discussed
with reference to the author' s previous works and other literature. An analysis of the
effect of tested voltage harmonics on measurement errors is conducted in Chapter 4,
with special emphasis on present-day loop impedance measurement methods and
instruments. Test and calculations of measurement errors were done for given types
of distorted waveforms and for different parameters of the tested circuit.
The theoretical principles governing the new loop impedance measurement
method, based on particular sampling, are presented in Chapter 5. Relations are derived
for determining the values of loop impedance, resistence and reactance in which
the influence of higher harmonics are eliminated. Chapter 6 deals with the practical
realization of the new method. A system loop impedance measuring instrument with
built-in microprocessor is presented. Examples of test measurement error results obtained
using the new instrument are also presented.
The present study contains extensive fragments of author Doctor of Science dissertation
published in the „Zeszyty Naukowe Politechniki Gdañskiej” No. 527 in
1995. Assemble the research work since 1995 of the author and his co-workers on the
measurement of loop impedance is posted on the end of references list of this elaboration..
6 Podręcznik