The relay protection tester is an important device for conducting protection logic testing in intelligent substations.However

the current relay protection testers on the market often face limitations such as a restricted number of analog output channels and lack of support for synchronized signal output across regions

making them unsuitable for cross-bay testing and long-distance differential protection testing in intelligent substations.To address these challenges

this paper proposes a relay protection tester control method based on a star topology.A system architecture featuring distributed computing with a master-slave model is designed to overcome limitations in analog output capacity and cross-regional synchronization.On the hardware level

the system employs a field programmable gate array (FPGA) for accelerated analog value computation and uses Ethernet to construct a star network topology

achieving time synchronization across devices.Test results demonstrate that the developed tester meets the demands of smart substation protection testing

including large-scale analog output control

high output accuracy

and long-distance synchronized analog signal output.