Post Commission Grid Impact Assessment of a 20 MWp Solar PV Grid Connected System on the ECG 33 kV Network in Winneba

Abstract

This paper summarizes the results of a post grid impact assessment of a Distributed Generated 20 MWp Solar PV plant on a 33-kV interconnection bus of a 161/33 kV substation within the Electricity Company of Ghana’s Limited distribution network located in the Gomoa Onyadze community in the Central Region of Ghana. The PV plant was commissioned since 2015. The paper assesses the impact of the PV plant in the following areas: The Demand Profile; Power Factor at the Point of Common Coupling (PCC); The Voltage Total Harmonic Distortion at the PCC; The Current Total Harmonic Distortion at the PCC; and the Voltage Profile at the PCC. The load profile was significantly distorted due to the active generation of the solar PV Plant. It now assumes a duck shape. The power factor at the 33 kV PCC bus deteriorated within the periods of active solar PV generation from 7:00 hours to 19:00 hours and went as low as 0.187 at noon time. The Voltage Total Harmonic Distortion (THD V) Levels at the 33 kV PCC bus where the solar PV Plant is interconnected, far exceeded the ECG allowable limits for THD V of 3%. The values were as high as 10%. The Current Total Harmonic Distortion (THD A) Levels at the 33 kV PCC bus of Transformer 1 far exceeded the limits of THD A of 5%. The values were as high as 65%. There was no significant impact on the voltage profile at the 33-kV bus where the solar PV plant was interconnected.