Degradation of low voltage metal oxide varistors in power supplies

Khanmiri, Dawood Talebi; Ball, Roy; Mosesian, Jerry; Lehman, Brad

doi:10.1109/apec.2016.7468160

Cited by 22 publications

(9 citation statements)

References 16 publications

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“…The main advantages of MOVs are its simplicity and high energy absorption capability with the typical value in the range of hundreds of joules per cubic centimetre [19]. However, it suffers from deterioration over time when frequently exposed to surges and overvoltage transients [20]. Furthermore, compared to the RCD snubber, it has no dv/dt control and displays larger transient oscillations during turn-off of SSCBs [21,22].…”

Section: Review Of Snubber Circuits For Sscbsmentioning

confidence: 99%

Design of a snubber circuit for low voltage DC solid‐state circuit breakers

Wang

Madathil

2021

IET Power Electronics

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Solid‐state circuit breakers (SSCBs) are designed to interrupt fault currents typically several orders faster than its electromechanical counterparts. However, such an ultrafast switching operation would produce a dangerous overvoltage which might cause damages to SSCBs and other circuit elements in the system. This paper proposes a novel snubber circuit for suppressing the overvoltage. It takes the advantages of both resistor‐capacitor‐diode (RCD) snubbers and metal oxide varistors (MOVs). Its operating process is analysed before the proposed snubber circuit for 400V DC SSCBs is designed. Pspice simulator is employed for simulating the operating process and a prototype SSCB with the proposed snubber is built and tested in a lab‐scale DC system. The results of simulation and experiment validate the effectiveness of the proposed snubber.

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Section: Review Of Snubber Circuits For Sscbsmentioning

confidence: 99%

Design of a snubber circuit for low voltage DC solid‐state circuit breakers

Wang

Madathil

2021

IET Power Electronics

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“…Nonetheless, ZnO SPDs are costly and difficult to inspect and diagnose using the basic maintenance procedures applied in distribution networks [12]. Due to the high current intensity and magnitude of energy of the atmospheric discharge, added to the large number of operations that ZnO SPDs must withstand, the physical limits of these devices are often exceeded, causing their damage or premature ageing and the failure of the circuit [13,14].…”

Section: Introductionmentioning

confidence: 99%

External Multi-Gap Lightning Arrester Modeling Using the Integration Method

Rodríguez-Serna,

Villa-Acevedo,

López-Lezama

2024

Energies

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Electric power distribution networks are exposed to both internal and external disturbances. Lightning strikes are among the latter and are responsible for a significant percentage of damage in distribution transformers, especially in rural areas. Electric utilities must pay special attention to prevent damage and service interruption due to these unforeseeable events. In this context, Surge Protection Devices (SPDs) combined with a series of external air gaps are designed to safeguard electric equipment and systems from transient over-voltages. There are several well-known models of SPDs in the specialized literature; nonetheless, few studies have been carried out with external gaps and multi-gaps. The main contribution of this paper is a methodology to model the disruptive effect in an external air gap by determining the parameters of Kind’s and Chowdhuri’s models using the integration method. The adjustment of the model parameters is carried out by a genetic algorithm (GA). The proposed model was tested and validated using experimental measurements, and its capability to predict the time-to-breakdown under different impulse voltages was verified.

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“…MOV arresters are designed to clamp both fast-and slow-front transient overvoltages to a safe voltage level lower than the basic insulation level (BIL) of the electrical equipment under surge protection. However, research carried out in this field shows that these overvoltage protection units often experience degradation and eventual failure as a result of a combination of factors, such as continuous AC and DC conduction, temperature, and the repeated discharge of high-magnitude surge currents [9][10][11][12][13][14]. Therefore, a condition assessment of MOV arresters is essential for the early detection of degradation.…”

Section: Introductionmentioning

confidence: 99%

Modelling of Low-Voltage Varistors’ Responses under Slow-Front Overvoltages

Muremi

Bokoro

Doorsamy

2023

Electronic Materials

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In this study, commercially low-voltage MOVs are exposed to switching surges to analyse and model the relationship between the number of surges and the MOV grain barrier height response. Repeated slow-front overvoltage transients are used to degrade the protective qualities of metal oxide surge arrester devices, affecting their reliability and stability. A total of 360 MOVs with similar specifications from three different manufacturers are degraded under switching surges at a constant temperature of 60 °C. The reference voltage and C-V characteristics of MOVs are measured before and after the degradation process to analyse the MOVs’ conditions. Grain barrier heights are determined from the C-V characteristics curve. An F-statistical analysis is then applied to analyse the effects of number of surges on the grain barrier height. The T-test is used to assess the statistical difference between the tested groups. Linear regression analysis is then applied to model the relationship between the number of surges and MOV grain barrier height. The results obtained show that the number of surges has a significant impact on grain barrier height. MOV grain barrier height is found to decrease as the number of surges applied increases. Regression models obtained for the tested MOV groups across all three manufacturers agree and indicate that the reduction in grain barrier height results from an increased number of surges. Regression coefficients of a developed model indicate that for one surge applied, the MOV grain barrier height decreases by 0.024, 0.055, and 0.033 eV/cm for manufacturers X, Y, and Z, respectively. Therefore, there is a linear relationship between grain barrier height and the number of applied switching surges.

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Degradation of low voltage metal oxide varistors in power supplies

Cited by 22 publications

References 16 publications

Design of a snubber circuit for low voltage DC solid‐state circuit breakers

Design of a snubber circuit for low voltage DC solid‐state circuit breakers

External Multi-Gap Lightning Arrester Modeling Using the Integration Method

Modelling of Low-Voltage Varistors’ Responses under Slow-Front Overvoltages

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