Monitoring of dips in the MV network for regulation- A case study

Abstract

Voltage dips constitute to a noticeable part of power quality (PQ) problems but causing major financial losses to industrial and commercial customers. This work involves comparative studies to choose the most appropriate location of monitoring dips for regulation. In this paper, a Dutch MV network is used and dip monitoring locations are considered at different points of connections (POC) where customers are connected. To estimate the number of dips per year, simulations are performed on the network using PowerFactory. The voltage dip profiles at the selected monitoring point are analyzed for phase and line voltage dips. The effects of distributed generation (DG) on the voltage dips are also observed and the transfer of voltage dips from MV to LV network is briefly discussed. To analyze the effects of the expected dips on industrial equipment, severity curves are applied onto the standard dip tables.

A proposal on voltage dip regulation for the Dutch MV distribution networks

“…Since then, PQ monitors have been introduced in the MV networks, and even more monitors are installed during 2014 to 2015 for continuous voltage dips measurements in the MV networks. As also recommended in the CIGRE/CIRED guidelines, permanent PQ measurements are mostly done on the MV side of the transformer in the HV/MV substations, which is considered as the most optimal monitoring location …”

“…As also recommended in the CIGRE/CIRED guidelines, permanent PQ measurements are mostly done on the MV side of the transformer in the HV/MV substations, which is considered as the most optimal monitoring location. 30 Voltage events (voltage waveforms with high time resolution) collected from 53 monitoring locations over different years of measurement period are used in this work. With this monitored data, phase-to-ground voltages are recorded in the MV networks.…”

Assessment of Voltage Dips based on Field Measurements in MV Networks

“…The voltage monitoring can be a part of PQ measurements which can be integrated into a multifunctional (protection, control, monitoring) system. In the Dutch MV networks, the PQ monitors are installed at the main busbar which is next to the HV/MV transformer-the most optimal location for monitoring voltage dips [12]. Such a system is the so called SASensor system which is implemented in several substations in the Netherlands and results in a significant amount of data acquisition [13].…”

Determining the Source of Dips Using Data of One Monitor in the MV Network

“…Because of economic constraint, the number of monitors installed in the MV distribution networks is restricted and this makes difficult to pinpoint the exact event location. From the data of a monitoring system in the MV distribution network, placed at the optimal location [8], voltage dip parameters including magnitude, duration and type can be obtained by diagnosing and characterizing the instantaneous values of voltage waveforms of the data [9], [10]. The data may include dips originating from the HV-or MV-networks which may be caused by short-circuit faults, energizing of transformers or switching of heavy loads.…”