This article presents the application of a multi-stage window comparator circuit with safety mode for swell voltage control in low voltage systems that lack stability and electrical quality. High-voltage transistors were used to build a simple voltage detecting circuit with multi-stage functions and electronic load to detect and control swell voltage. SVSS as the overloaded energy receptor resulted in clamping voltage. The voltage of a device is equal to the voltage flowing to smart electronic loads and not over the IEEE 1159 and 1100 standards. The device worked normally without causing damages. Failure Mode and Effect Analysis (FMEA) might occur using a multi-stage window comparator circuit in the safety mode. The reliability and stability in detecting voltage and controlling electronic loads to work safely under many kinds of situations were also assessed.

This article presented the application of a safety comparator in the track circuit of a railway signaling system for counting the overvoltage caused by voltage fluctuation resulting in the damage of the BR966F2 relay. Overvoltage counting in the track circuit of the railway signaling system using the safety comparator to detect two voltages in the series circuit and the fault of overvoltage of the track circuit were used for detecting the status of the train in the interlocking system of the railway signaling system, and the digital counter circuit displaying the overvoltage status to monitor and confirm the use of the BR966F2 relay of the railway signaling system that resolved the problem causing the track circuit error, minimized the duration for system maintenance, and maximized the reliable performance of the advanced safety system in the track circuit for the control and command functions of the railway’s operations of the State Railway of Thailand.

This study was aimed to present a Technical loss analysis of the Provincial Electricity Authority (PEA) in Hatyai. To determine the technical loss in the distribution system included are Transmission Line Losses, Power Transformer Losses, Distribution Line Losses and Lowvoltage Transformer and Distribution Line Losses. It was found that Low-voltage Transformer and Distribution Line Losses had a maximum value of 79 % and Technical loss was at 3.43. So in controlling or decrease Technical loss, the appropriate and correct method had to be selected by investigating both cost and worth. This study was also to determine distribution line losses by electrical model and to report on the power losses evaluation method as an improvement method to reduce the investigation cost for both transformer and capacitor selection. The study further aims at increasing the efficiency and reliability of the distribution system by reducing Technical Losses by increasing feeder size, power factor correction, reducing feeder impedance, lower transformer losses. It was discovered that line losses have much value at the end line. This was found to decrease when loads have constant distribution and are near the source. That is, line losses have lower value when lead lines have a larger size. Both load distribution and lead line sizes were observed to affect distribution line losses.

This research introduces a safety hysteresis comparator that detects transient overvoltage in the track circuit relay interlocking of railway signaling system. This overvoltage is caused by voltage faults transmitted through the electric conductor on the track feed unit to the receiver equipped with the track relay, which acts as the occupied track circuit controller. The circuit was designed using safety system design principles and concepts. Findings illustrated that the transient overvoltage detection of the safety hysteresis comparator in the track circuit activated when the input voltage (Vin) was higher than the high hysteresis signal level (Vhyst_H). When Vin was less than low hysteresis signal level (VVhyst_L), the output voltage (Vo) state was low. Otherwise, it was high. The hysteresis voltage was 4.4 V. The installation of the transient overvoltage detector in the track circuit was to monitor the transient overvoltage fault in the track circuit and to confirm that the hysteresis comparator was in the safety failure mode, which was the safety function for the track circuit to be compliant with the IEC 61800-5-2 standard to ensure the system stability and reliability. It would maximize the performance of the controlling function and commanding of train arrangement of State Railway of Thailand (SRT).

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This research presented the utilization of Safety Transient Voltage Suppressors (STVS) in the track circuits of railway signaling systems, occurring during circuit switching due to changes in track occupancy conditions, resulting in damage and malfunction of the BR966F2 relay. The study employed Failure Modes and Effect Analysis (FMEA) combined with 1kV actual transient overvoltage testing featuring a waveform slope of 184/380 μs. Results revealed two transient voltage suppression levels encompassing Set A_(a,b), Set B_(a) and Set C_(a,b) as well as Set A//Set B//Set C and All Mode. These configurations achieved a clamping voltage of 41.6 V, categorized as Stage 1. Configurations like Set A_(c), Set B_(b,c) and Set C_(c) displayed increased series circuit behavior leading to a clamping voltage of 48.6 V, categorized as Stage 2. The application of STVS device in the track circuit of the signaling system reduced the transient voltage by diversion of the Transient Current or ISTVS through the STVS device into the ground system or the clamping voltage at the STVS device. This prevented the transient power from flowing into and damaging the relays of the track circuit, leaving only the clamping voltage with a missing peak wave. This contributed to the stability of the track circuit within the railway signaling system while also raising the Safety Integrity Level (SIL) to a higher standard, in accordance with the specifications of IEC 16508-4 and the unique requirements of the State Railway of Thailand. These enhancements increased the advanced safety system within the track circuit, particularly for train control and train operation functions of the State Railway of Thailand