Estimate the Temperature Rise of Medium Voltage Metal Enclosed Switchgear by Simplified Heat Transfer Calculations

Abstract

Electrical equipment will experience a rise in temperature during normal operation. During a development process, prototypes and laboratory tests will be required to make sure the temperature rises are within acceptable limits as defined by standards. The aim of having a tool to predict the temperature rise, is to reduce the number of prototypes and test loops needed in the laboratory during a development period. Advanced simulation tools such as CFD can give valuable results, however, they require expertise user and extensive compute and manpower allocation. This paper presents a practical design approach developed for providing a first, quick and rough estimate of the temperature rise of the most critical parts in an air insulated switchgear. The main idea behind the method is to first use the method described in IEC 60890 to estimate the temperature rise of the gas inside the switchgear. Then, simplified heat transfer calculations are used to estimate the over-temperature of critical parts relative to the surrounding gas. The accuracy of the temperature estimates will depend on how well the power input is known, especially the contact resistances. Further, it may be challenging to predict the influence of large metallic construction elements that may function as heat sinks.

An innovative method to conduct temperature rise test on medium voltage switchgear assembly based on IEC standards in a power grid

“…The organic or inorganic insulating system is found in various power devices [1, 5, 7, 15]. Aside from the electric field intensity, partial discharges, and other similar electrical phenomena that occur as a result of its action, temperature is a key service component that primarily influences the lifetime of electrical insulation systems [1–3, 8, 12]. As a result, temperature might be viewed as a particularly important ageing factor for power electronics.…”

“…When dealing with the early stages of switchgear design, such a strategy could be useful [4][5][6][7]. The research on the temperature distribution in the switchgear is crucial for the optimum design consideration and maximizing the service life of the switchgear [1][2][3][4]. Hence, many scholars have launched a series of research with computer simulation on the temperature distribution of the switchgear.…”

“…Typical stress factors are abnormal environments or abnormal operating conditions. As a load of power systems continuously grows, the switchgear's capacity continues to climb, resulting in the overheating in the switchgear becoming more serious [1][2][3]. The higher current capacity in the switchgear will increase the heat dissipated naturally.…”

“…Different approaches are available for thermal stimulation in terms of modelling complexity. The researchers use additional available computer software such as the Finite Element Method, COMSOL Multiphysics, Computational Fluid Dynamic solver, ANSYS etc [1,4].The simulation required the accurate calculation of mathematical and numerical models to obtain the switchgear's temperature distribution [8]. Although this technique is widely applied, researchers experienced the difference between computer simulation value and actual experimental setup [9].…”

Temperature Distribution Simulation in an MV Switchgear Bus Bar Chamber

“…In the technical regulation for MV switchgear guidance PD CLC IEC/TR 62271-307:2019, it is highlighted that temperature rise calculations within MV switchgear can be evaluated according to low voltage (LV) assembly technical report IEC/TR 60890. In [3] an approach for the estimation of the temperature rise of circuit breaker contacts based on that report within an air insulated MV switchgear is conducted. It is also known that in LV cabinets a uniform heat distribution is considered whereas this is not the case in MV switchgear.…”