Study on Insulator Flashover Voltage Gradient Correction Considering Soluble Pollution Constituents

Abstract

Natural polluted insulator surfaces are always coated with various kinds of soluble constituents, and those constituents affect flashover performance differentially. Currently, this fact is not considered either in laboratory experiments or field pollution degree measurements, causing the existing insulation selection method to be deficient. In this paper, a systematic study on insulator flashover voltage gradient correction involving different types of soluble pollution constituents is presented. Using a typical type glass insulator as the sample, its flashover tests, polluted by typical soluble chemicals (NaCl, NaNO 3 , KNO 3 , NH 4 NO 3 , MgSO 4 , Ca(NO 3 ) 2 and CaSO 4 ), were carried out. Then, the flashover gradient correction was made by combining the flashover performance of each soluble constituent, the equivalent salt deposit density (ESDD) contribution of the seven constituents, and the saturation performance of CaSO 4 . The correction agreed with the flashover test results of insulator polluted by three types of soluble mixture. Research results indicate that the flashover gradient correction method proposed in this paper performs well in reducing the calculating error. It is recommended to carry out component measurements and flashover gradient correction to better select outdoor insulation configuration.

Experimental Study and Modeling of the Effect of ESDD/NSDD on AC Flashover of SiR Outdoor Insulators

“…Based on Table 6, discharge parameters N and n vary with the insoluble amount: both N and n decrease with NSDD. The results are in accordance with the results observed in [8,34] and confirmed by [11,17]. This can be related to the effect of the pollution constituent on the discharge temperature, as proposed in [8,27].…”

“…By combining ( 5) and (10), it yields (11) Equation (11) shows that the flashover voltage depends on the pollution level, form factor, NSDD amount, and arc characteristics.…”

“…The pollution degree is defined by the equivalent salt deposit density (ESDD) and represents the concentration of NaCl that, when dissolved in demineralized water, gives the same volumetric conductivity as that of the natural deposit removed from a given surface of the insulator divided by the area of the surface, generally expressed in mg/cm 2 . However, in the real field, the pollution constitution depends on the local environment where NaCl is not the predominant salt, as established by many researchers [7,8,[11][12][13][14][15]. On the other hand, the pollution layer contains insoluble materials consisting mainly of ferrite, silica, and alumina [4,9,13,[15][16][17][18].…”

Application of Artificial Neural Network in Predicting Flashover Behaviour of Outdoor Insulators under Polluted Conditions

“…The chemical constituents of pollution deposited on the insulator surface also affect flashover performance. [6] concluded that the flashover voltage of outdoor insulators depends on the soluble substance, their type and chemical composition. Daochun, et al [7] reported that Non-Soluble Salt Deposit Density (NSDD) also have an impact on flashover characteristics and in the slurry the size of particles in nonsoluble material is the primary reason affecting flashover.…”

Prediction of Critical Flashover Voltage of High Voltage Insulators Leveraging Bootstrap Neural Network

“…With the increase in transmission line voltages and increased distance of renewable power sources from the loads, the importance of research on the pollution performance of insulators has significantly increased. The mechanism of flashover in high voltage porcelain, glass, and ceramic insulators under contamination has been studied extensively in the past [14][15][16]. Many researchers have proposed mathematical models to predict the critical flashover voltage under uniform and non-uniform pollution [17,18].…”