A comprehensive review of existing radial distribution test systems available for power system distribution research is presented. The review can be used to establish a record of cases suitable for distribution operation and planning studies. The importance of the distribution system, the structure of the system in the grid, and various configurations of the distribution network are discussed. The primary requirement of a distribution network is highlighted to underline the important system parameters that should be considered in the design and planning stages. Various research related to the distribution network can be conducted, such as load flow algorithms, optimal incorporation of distributed generation, network reconfiguration, and optimal capacitor allocation, such as important details pertaining to each test system are given. Additional information, such as active and reactive loads and losses, minimum voltage values, and bus location with the weakest voltage values, is provided. Application of the reviewed works based on the test system is tabulated and presented. The information presented in this paper will be beneficial for future research in distribution system design and planning
