Impact of Changes in a Distribution Network Nature on the Capacitive Reactive Power Flow into the Transmission Network in Slovakia

Matej Tazky,Alena Otcenasova,Michal Regula

doi:10.3390/en14175321

Abstract

The main emphasis in the operation of an electricity system is placed on its safe and reliable operation. The flow of reactive power in a network can affect voltage conditions in individual nodes of the transmission system. In recent years, there have been changes in the network that have resulted in increased capacitive reactive power flows from lower voltage levels to higher ones. These flows can cause the voltage to rise above the limit. This paper examines recent changes in the reactive power transmission in the network, especially at lower voltage levels. The possible impact of these changes on the flow of capacitive reactive power at higher voltage levels is analyzed. This paper also presents a description and the simulated impact of power lines at different voltage levels on reactive power flows. Real measurements of different types of consumers at the low-voltage (LV) level are analyzed. Finally, a simulation model was created to simulate the impact of a customer’s power contribution to the reactive power flows from the point of view of a 110 kV voltage node. This node is characterized as a supply point.

Highlights

The level of reactive power in a network is reflected in the voltage [1,2]
The aim of this article is to analyze and determine possible sources of capacitive reactive power flow in the network, which is growing due to changes in the network
The effect of power line cabling was significant and has a strong impact on reactive power flow, with an increased length of cable lines of only 10%

Summary

Introduction

The level of reactive power in a network is reflected in the voltage [1,2]. Safe and reliable operation is a basic requirement of an electricity system [2,3,4]. The flow of reactive power in the system may affect the quality of this operation. An abrupt shutdown of a single transmission line may be a local problem. An example is the recent outages of several network elements in January 2021. This started by disconnecting a single transmission line as a reaction to an overcurrent protection device signal. The result was the division of the common interconnected European system (ENTSO-E) into two parts with different frequencies [5]

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Discussion

Conclusion