Consequences of smart grids for power quality: Overview of the results from CIGRE joint working group C4.24/CIRED

Design of a Distributed Signal Processing Unit for Transmission Line Protection in a Centralized Substation Protection Architecture

“…The signal i s,3φ (t) has been band-limited by a 2 nd order Butterworth filter with a cutoff frequency of 400 kHz representing the analog anti-aliasing filter of the DSPU. This leads to an oversampled discrete-time quantized signal x 3φ [n] with F s = 1 MHz according to (1). The Fig.…”

“…Digital signal processing (DSP) plays a vital role in power system protection for extracting different features of the voltage and current signals such as the fundamental phasor components, RMS values or the 2 nd to 5 th harmonic components. The importance of DSP in protection systems will increase due to power system phenomena such as increased magnitudes of harmonics and interharmonics [1], in particular subharmonics, as well as reduced system inertia and reduced short circuit ratio (SCR) [2]. These phenomena are mainly caused by an increasing number of inverter-connected generation and other non-linear loads.…”

“…The input signals of the DSPU are the three-phase continuous functions x(t) of secondary currents and voltages, which have been band-limited by analog antialiasing filters to the Nyquist frequency F N = 500 kHz. Thus the band-limited function x(t) can be uniformly sampled with a sampling frequency F S = 1 MHz and the discrete-time quantized signal x[n] is obtained as shown in(1).…”

Estimation of Harmonics in Partly Monitored Residential Distribution Networks With Unknown Parameters and Topology

“…• In the estimation method, the probability distribution of harmonic current injections of each consumer is estimated with the measurements registered by PQ monitors during the previous week. • A ratio r/x = 5 is used for the parameters shown in (8).…”

“…V OLTAGE harmonic distortion in residential distribution networks (RDN) is arousing increasing concern and interest from both, distribution system operators (DSO) and academia [1]- [6]. With the aim of improving efficiency and decarbonizing the economy, a generalized adoption of powerelectronic-based devices has taken place in recent years in the residential sector, leading to an increase in voltage and current distortion levels [7], [8]. That is the case, for instance, of lighting, where conventional linear loads (i.e., incandescent lamps) have been massively replaced by compact fluorescent lamps (CFLs) and later by light-emitting diodes (LEDs) [9].…”