ANALYSIS OF COORDINATION BETWEEN PRIMARY AND SECONDARY PROTECTORS

This paper provides circuit models for analyzing the coordination betw een primary and secondary surge protectors, Although the analysis is p erformed in the context of lightning surges on telecommunication circu its, the models developed are generic in nature and can be used to ana lyze the interaction of cascaded surge protectors under voltages produ ced either by lightning or by power line disturbances. Equivalent circ uits are developed for calculation of voltages and currents at prim my and secondary protectors, Formulas are provided and procedures are de scribed for achieving the best coordination between primary and second ary protectors. Two different configurations are analyzed for protecti on coordination. In the first configuration the primary and secondary protectors connect between each conductor of the cable pair to ground. In the second configuration, a secondary protector is located between two conductors of a cable pair while the primary protector is located from each conductor to ground.