The transient stability of a power system is the stability of the system when it is subjected to a large and sudden disturbance. The time frame of the transient stability is the first 1 to 2 sec. The most powerful and cheapest tool for transient stability augmentation of a power system is the dynamic braking resistor. Instants of switching are decided using the rate of change of kinetic energy (RACKE) as well as the speed of the disturbed machine. The RACKE idea was studied previously using the off-line computer simulation, and proved its powerfulness for deciding system stability and its effectiveness for increasing stability margin when dynamic brake elements are used. The main concern in the present work is the practical implementation of RACKE method. The stability of a single machine, which is connected to an infinite bus, is examined theoretically and practically. The brake insertion and removal instants are controlled by a real-time control algorithm which is implemented on a personal computer to satisfy the time frame of transient stability problem. So that the measured values are read from the input devices, processed and the results are used to generate the control signals that maintain system stability within an acceptable limit. The operation of the system input/output devices must be synchronized in real-time with the execution time of the program controlling data transfer. Thus, hardware circuitry and software algorithm are carefully designed. Several electronic circuits were designed and implemented to satisfy the time frame of the transient stability. An interfacing card was designed to interface the PC with outside world, ancillary circuits were built to monitor the speed and the rotor angle of the generator during the transient condition, and to show the effectiveness of the brake on the power system simulator (PSS) during this time. An efficient and fast response language with the interrupt operation are used to interface the power system simulator with the microcomputer. Since RACKE method depends on the deviation speed of the generator as the only measured value to define system stability, it requires a fast and accurate speed measuring circuit. In this work the speed measuring circuit for a wide speed range with high accuracy and fast response time was implemented. So that the real-time implementations of RACKE calculation and brake controlling can be achieved successfully. The integrated system performance indicates that the implementation of the RACKE switching strategy yields a precise timing for insertion and removal of the dynamic brake, gives a wider stability margin, and at the same time it directly decides at the last switching operation whether the system is stable or not.