Numerical calculation of the corona onset voltage for bundle conductors for HVDC transmission line

Li, Zhongxin; Li, Guangfan; Fan, Jian-Bin; Yin, Yu

doi:10.1002/etep.406

Cited by 10 publications

(11 citation statements)

References 14 publications

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“…Corona discharges are self-sustained electric discharges, which ionize a reduced region around the high-voltage electrode. They occur when the surface electric field exceeds the critical inception value, as recognized in [6,7] when analyzing transmission power lines. When the surface electric field is above the critical inception value, air molecules can be ionized [8] due to electron collision, thus developing an electron avalanche process [9].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of AC and Positive and Negative DC Visual Corona for Sphere-Plane Gaps in Atmospheric Air

2018

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Due to the expansion of high-voltage direct current (HVDC) power systems, manufacturers of high-voltage (HV) hardware for alternating current (ac) applications are focusing their efforts towards the HVDC market. Because of the historical preponderance of ac power systems, such manufacturers have a strong background in ac corona but they need to acquire more knowledge about direct current (dc) corona. Due to the complex nature of corona, experimental data is required to describe its behavior. This work performs an experimental comparative analysis between the inception of ac corona and positive and negative dc corona. First, the sphere-plane air gap is analyzed from experimental data, and the corona inception voltages for different geometries are measured in a high-voltage laboratory. Next, the surface electric field strength is determined from finite element method simulations, since it provides valuable information about corona inception conditions. The experimental data obtained are fitted to an equation based on Peek’s law, which allows determining the equivalence between the visual corona surface electric field strength for ac and dc supply. Finally, additional experimental results performed on substation connectors are presented to further validate the previous results by means of commercial high-voltage hardware. The results presented in this paper could be especially valuable for high-voltage hardware manufacturers, since they allow determining the dc voltage and electric field values at which their ac products can withstand free of corona when operating in dc grids.

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Section: Introductionmentioning

confidence: 99%

Comparative Study of AC and Positive and Negative DC Visual Corona for Sphere-Plane Gaps in Atmospheric Air

2018

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“…Therefore, there is a pressing need to detect such harmful effects in the early stage by using suitable sensing systems. Among the standard systems to detect corona activity, the partial discharge and radio interference voltage measurements are highlighted, although such methods require very low levels of electromagnetic noise, thus requiring screened facilities, sophisticated, and very expensive and bulky Results from Figure 11 clearly show that the breakdown voltage according to the Paschen's curve for air is much beyond the CEV, with this difference depending on the configuration of the experimental setup (20,30, and 40 mm gap). Therefore, the CEV value is much more limiting than the values of the Paschen's curves, so full consideration must be given to the CEV value when designing high-voltage systems for aerospace applications, although the difference between both values tends to vanish at very low p·d values.…”

Section: Discussionmentioning

confidence: 99%

“…A corona is a type of partial discharge occurring in a gaseous dielectric, i.e., a discharge producing incomplete electrical breakdown of the interelectrode gap, which occurs under non-uniform field conditions whose strength is not sufficient to produce electrical breakdown [19]. Corona discharges take place when the field at the outer surface of a high-voltage electrode is beyond a critical value [20][21][22] since the molecules of the gaseous medium are likely to be ionized [23] because of collisions with electrons, thus initiating a cascade or avalanche of electrons under the influence of an intense electric field which is capable of accelerating the generated free electrons to ionization speeds. It is believed that the initial electrons can be generated by cosmic rays and energetic photoelectrons, which are more abundant and energetic at high altitudes.…”

Section: Corona Effect and Arc Trackingmentioning

confidence: 99%

“…Figures 7 and 8 show the sequence of the long exposure corona photographs taken by the Sony IMX29 back-illuminated CMOS camera according to the procedure detailed above, under positive and negative DC supply, respectively. Figure 9 shows the CEV values recorded at the different heights of the sphere above the ground plane (20,30, and 40 mm) versus the pressure of air. The results provided in Figure 9 show an almost linear behavior of the CEV values versus the pressure, for both positive and negative DC polarities of the applied voltage.…”

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confidence: 99%

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Experimental Study of Visual Corona under Aeronautic Pressure Conditions Using Low-Cost Imaging Sensors

Riba

Gómez-Pau

Moreno-Eguilaz

2020

Sensors

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Visual corona tests have been broadly applied for identifying the critical corona points of diverse high-voltage devices, although other approaches based on partial discharge or radio interference voltage measurements are also widely applied to detect corona activity. Nevertheless, these two techniques must be applied in screened laboratories, which are scarce and expensive, require sophisticated instrumentation, and typically do not allow location of the discharge points. This paper describes the detection of the visual corona and location of the critical corona points of a sphere-plane gap configurations under different pressure conditions ranging from 100 to 20 kPa, covering the pressures typically found in aeronautic environments. The corona detection is made with a low-cost CMOS imaging sensor from both the visible and ultraviolet (UV) spectrum, which allows detection of the discharge points and their locations, thus significantly reducing the complexity and costs of the instrumentation required while preserving the sensitivity and accuracy of the measurements. The approach proposed in this paper can be applied in aerospace applications to prevent the arc tracking phenomenon, which can lead to catastrophic consequences since there is not a clear protection solution, due to the low levels of leakage current involved in the pre-arc phenomenon.

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“…First, starting from the corona onset model, the corona onset electric field of the transmission line is studied. Li et al ., based on the charge simulation method, gave a numerical calculation method of the corona onset voltage for bundle conductors for the high voltage direct current (HVDC) transmission line . Lu et al .…”

Section: Introductionmentioning

confidence: 99%

Calculation method of corona loss in EHV/UHV system based on distributed parameter characteristic

Pan

Chen

2018

IEEJ Transactions Elec Engng

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For the calculation of corona loss of extra-/ultra-high voltage (EHV/UHV) transmission lines, especially the estimation of realtime corona loss, there exists no accurate method. In this paper, a calculation method of corona loss in the EHV/UHV system based on a distributed parameter characteristic is proposed. Based on the π -shaped equivalent circuit of the long-line distributed parameter characteristic, and considering the voltage distribution along the line, a formula for calculating the corona loss under a variety of weather and annual average conditions is derived and the power equation for the corona loss of EHV/UHV system is established by the method. The example results show that the method is quite accurate. The calculation method of this paper can consider different weather conditions of the line sections to calculate the corona loss. It is more in line with the actual weather conditions on the surface of the EHV/UHV transmission lines. And the method can analyze the corona loss and its proportion to the total loss of the system under the annual average and different weather conditions. It is of great significance to the design and operation of an EHV/UHV system.

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Numerical calculation of the corona onset voltage for bundle conductors for HVDC transmission line

Cited by 10 publications

References 14 publications

Comparative Study of AC and Positive and Negative DC Visual Corona for Sphere-Plane Gaps in Atmospheric Air

Comparative Study of AC and Positive and Negative DC Visual Corona for Sphere-Plane Gaps in Atmospheric Air

Experimental Study of Visual Corona under Aeronautic Pressure Conditions Using Low-Cost Imaging Sensors

Calculation method of corona loss in EHV/UHV system based on distributed parameter characteristic

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