This paper examines a 33kV medium voltage distribution network for improved performance, and five (5) medium voltage feeders from Port Harcourt mains transmission were analyzed. Simulation was performed in electrical transient analyzer program software (ETAP 19.1) using the Newton-Raphson load flow technique. The results obtained from the base case network simulation show that the following buses violated the statutory limit condition of 0.95-1.05p.u (Aba Road 93.03%, Agip 93.03%, and Okoh Road 93.03%, Federal Government College (FGC) 91.98%, Obi-wali 91.98%, Eligbolo 91.98%, and Rukpokwu 91.98%,). Also, the transformer T-4 (96.80%), T-5 (96.50%), and T1A (104.30%) were overloaded. It was observed that under-voltage experienced is due to the overloading of transformers T-4 and T-5 at the Oporo and Rumuodomaya injection substations. The total real and reactive power losses in the base case were 148.6 kW and 251.2 kvar. However, transformer up-gradation was used as the cost-effective optimization technique to improve the network of Oporo and Rumuodomaya injection substations. The operating values after optimization for the buses and transformers are (Aba Road 98.91%, Agip 98.91%, Okoh Road 98.91%, FGC 98.23%, Obi-wali 98.23%, Eligbolo 98.23%, and Rukpokwu 98.23%,) and transformers loading reduced T-4 (50%), T-5 (58%), and T1A (56.8%). We concluded that the proposed optimization techniques impacted significantly in the improvement of the 33kV medium voltage distribution network.