Acting as the single-processor master control unit, the SPU232.2 utilizes the rack backplane bus and an isolated CAN bus to perform data aggregation and processing for the entire system. Analog signals—such as generator terminal voltage, rotor current, and stator current—are fed into the PIB101 measurement board for signal conditioning, while binary signals (e.g., circuit breaker status and excitation switching commands) are acquired by the DIZ232 digital input board; all acquired data is transmitted to the SPU232.2 via the backplane. The boards scan and acquire signals at fixed intervals, performing analog-to-digital conversion and noise filtering. The unit then executes built-in excitation PID control algorithms and various limiting and protection models to calculate the firing angle command for the excitation thyristors, subsequently transmitting this command to the ICP232 module.

The 855GME chipset allows the VMIVME-7807/VME-7807RC to provide enhanced features such as integrated video and Ultra ATA/100 IDE support. The VMIVME-7807/VME-7807RC are capable of executing many of today’s desktop operating systems such as Microsoft®’s Windows® XP, Windows 2000 and a wide variety of Linux® based operating systems. The standard desktop features of the VMIVME-7807/VME-7807RC are described in Chapter 2 of this manual.

The fault locator is an impedance measuring function giving the distance to the fault in percent, km or miles. The main advantage is the high accuracy achieved by compensating for load current and for the mutual zero-sequence effect on double circuit lines.

To achieve fast clearing of faults on the whole line, when no communication channel is available, local acceleration logic (ZCLCPLAL) can be used. This logic enables fast fault clearing during certain conditions, but naturally, it can not fully replace a communication channel.

The line differential communication can be arranged as a master-master system or a master-slave system alternatively. In the former, current samples are exchanged between all IEDs, and an evaluation is made in each IED. This means that a 64 kbit/s communication channel is needed between every IED included in the same line differential protection zone. In the latter, current samples are sent from all slave IEDs to one master IED where the evaluation is made, and trip signals are sent to the remote ends when needed. In this system, a 64 kbit/s communication channel is only needed between the master, and each one of the slave IEDs.

10° to 35°C (50° to 95°F) at sea level with an altitude derating of 1.0°C per every 305 m (1.8°F per every 1000 ft) above sea level to a maximum of 3050 m (10,000 ft); no direct sustained sunlight. Maximum rate of change is 10°C/hr (18°F/hr). The upper limit may be limited by the type and number of options installed.

　10° to 35°C (50° to 95°F) at sea level with an altitude derating of 1.0°C per every 305 m (1.8°F per every 1000 ft) above sea level to a maximum of 3050 m (10,000 ft); no direct sustained sunlight. Maximum rate of change is 10°C/hr (18°F/hr). The upper limit may be limited by the type and number of options installed.