<p>The reliability of relay coordination in distribution networks becomes increasingly critical in hybrid distribution systems with the integration of Distributed Energy Resources (DERs). With more and more DERs plugging into the grid, it has become increasingly important to undertake relay coordination in distribution networks. These DERs turn traditional distribution networks into hybrid distribution systems, wherein the operating time setting of directional overcurrent relays must be chosen such that coordination constraints are satisfied. The aim is quick and selective fault clearance. To this end, the paper presents a novel hybrid optimization technique, referred to as CI-PSO, that combines the wide searching capability of CI with the fast convergence of PSO. The performance of the proposed CI-PSO approach is compared with those obtained using four well-known approaches: Genetic Algorithm, PSO, Differential Evolution, and standalone CI. The tests are conducted on standard IEEE 3-bus, 8-bus, and 15-bus networks and a practical 3-bus distribution setup under two scenarios-case 1 with two generators and case 2 with the inclusion of one additional future DER unit. The outcome indicates that the CI-PSO delivers the shortest relay operating time in all cases, demonstrating better efficiency and suitability for relay coordination in distribution systems integrated with DER. In the IEEE distribution test cases, CI-PSO reduces the total DOCR operating time by 8.0, 8.1, 8.8 and 18.1% compared to GA, DE, PSO and CI, respectively, with the smallest standard deviation, reflecting its faster and more reliable convergence.</p>