The selection of busbar trunking systems is crucial for operational safety and reliability in electrical power systems. However, harmonic currents created by semiconductor-based converters reduce the current carrying capacity of busbar trunking systems, especially in electric vehicle charging stations, energy storage systems, microgrids, and data centers. In this case, busbar trunking systems with two neutrals or increased cross-section could be used for operating conditions with harmonic currents. Therefore, this study examines the thermal performance of the busbar trunking systems with different design parameters when loaded with harmonic currents. For this purpose, coupled electromagnetic field and thermal analyses were carried out using the finite element method. As expected, the results show that the maximum temperature in the temperature distributions increases significantly when busbar trunking systems are loaded with non-sinusoidal currents. Furthermore, the analysis studies determined the loading limits of busbar trunking systems within the thermal restriction when operating with non-sinusoidal currents. Accordingly, depending on the conductor’s phase sequences, the busbar trunking system model with one neutral conductor can be loaded with between 20% and 25%, two neutral conductors model can be loaded with between 22% and 39%, and the busbar trunking system model with 25% increased conductor cross-sections can be loaded with between 39% and 44% harmonic current. The results show that in the case of loading with non-sinusoidal currents, especially at a high portion of third harmonic components, choosing a busbar trunking system with a high cross-section area is advantageous compared to using two neutral conductors. This information is crucial to system reliability in electrical power system design. Therefore, it has become necessary to conduct these evaluations according to the equipment used while designing the electrical power system.

Busbar trunking systems (BTS) are one of the preferred solutions for energy distribution in electrical power systems. Due to its modular structure and easy installation, BTS are widely used in industrial facilities, commercial centers, data processing facilities, hospitals, airports, electric vehicle charging stations, energy storage systems, and microgrid systems. In addition, it is preferred because of its technical and economic advantages compared to cable systems [1]. Busbar modules can be produced compactly in a broad current carrying capacity range. The main feature that determines the current carrying capacity of the busbar module is the conductor cross-section and the thermal behavior of the busbar module. The thermal behavior of the busbar module is directly affected by the total harmonic distortion (THD) of loading current. If the current through the conductors contains third harmonic component, a current occurs in the neutral line since the phasor sum of third harmonics of different phases is not zero. Therefore, this current negatively affects distribution systems, which can reach high values carried by the neutral line. Due to the excessive heating of BTS in case of loading with harmonic currents, material deformation and fires could occur. In addition, semiconductor-based converters usually create harmonic currents. For example, electric vehicle charging stations, energy storage systems, microgrids, solar power plants, and wind power plants contain converters consisting of industrial rectifiers and inverters at high power. Also, many rectifiers are used in places such as hospitals, businesses and shopping centers at low power. Therefore, it is necessary to design the electrical power system in such facilities by evaluating the THD value while sizing the busbar trunking system.

Read more: Influence of busbar trunking system design on thermal performance operating with non-sinusoidal currents