### Abstract

Effects of superposition of a low-frequency (0.1 to 50 Hz) voltage and a high-frequency 2 kHz voltage on the growth of water trees in polyethylene are examined. It has become clear that both the number of total voltage zero-crossings during the whole voltage application period and the number of consecutive voltage zero-crossings in the instant of the polarity reversal of the low-frequency voltage play important roles in the length and shape of water trees. Namely, the water tree length becomes longer as the number of total zero-crossings increases. Furthermore, among the voltages with the same number of total zero-crossings, the length becomes even longer with a prolonged shape in the direction of electric field as the number of consecutive zero-crossings increases. Effects of superposition of a high-frequency voltage onto a dc voltage are also examined. In this case, the dc voltage seems not to have any influence to the tree growth. By assuming the presence of space charge around the water-tree tip, the effective zero-crossings become only sensitive to the high-frequency component. Therefore, this result also indicates that the number of voltage reversals at the tree tip plays a crucial role in the growth of water trees.

Original language | English |
---|---|

Pages (from-to) | 708-714 |

Number of pages | 7 |

Journal | IEEE Transactions on Dielectrics and Electrical Insulation |

Volume | 11 |

Issue number | 4 |

DOIs | |

Publication status | Published - 2004 Aug |

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### Keywords

- Low density polyethylene
- Polymeric insulation
- Power cable
- Tree length
- Water tree

### ASJC Scopus subject areas

- Electrical and Electronic Engineering

### Cite this

*IEEE Transactions on Dielectrics and Electrical Insulation*,

*11*(4), 708-714. https://doi.org/10.1109/TDEI.2004.1324360

**Role of number of consecutive voltage zero-crossings in propagation of water trees in polyethylene.** / Kaneko, Daisaku; Maeda, Tomoya; Ito, Toshihide; Ohki, Yoshimichi; Konishi, Takeshi; Nakamichi, Yoshinobu; Okashita, Minoru.

Research output: Contribution to journal › Article

*IEEE Transactions on Dielectrics and Electrical Insulation*, vol. 11, no. 4, pp. 708-714. https://doi.org/10.1109/TDEI.2004.1324360

}

TY - JOUR

T1 - Role of number of consecutive voltage zero-crossings in propagation of water trees in polyethylene

AU - Kaneko, Daisaku

AU - Maeda, Tomoya

AU - Ito, Toshihide

AU - Ohki, Yoshimichi

AU - Konishi, Takeshi

AU - Nakamichi, Yoshinobu

AU - Okashita, Minoru

PY - 2004/8

Y1 - 2004/8

N2 - Effects of superposition of a low-frequency (0.1 to 50 Hz) voltage and a high-frequency 2 kHz voltage on the growth of water trees in polyethylene are examined. It has become clear that both the number of total voltage zero-crossings during the whole voltage application period and the number of consecutive voltage zero-crossings in the instant of the polarity reversal of the low-frequency voltage play important roles in the length and shape of water trees. Namely, the water tree length becomes longer as the number of total zero-crossings increases. Furthermore, among the voltages with the same number of total zero-crossings, the length becomes even longer with a prolonged shape in the direction of electric field as the number of consecutive zero-crossings increases. Effects of superposition of a high-frequency voltage onto a dc voltage are also examined. In this case, the dc voltage seems not to have any influence to the tree growth. By assuming the presence of space charge around the water-tree tip, the effective zero-crossings become only sensitive to the high-frequency component. Therefore, this result also indicates that the number of voltage reversals at the tree tip plays a crucial role in the growth of water trees.

AB - Effects of superposition of a low-frequency (0.1 to 50 Hz) voltage and a high-frequency 2 kHz voltage on the growth of water trees in polyethylene are examined. It has become clear that both the number of total voltage zero-crossings during the whole voltage application period and the number of consecutive voltage zero-crossings in the instant of the polarity reversal of the low-frequency voltage play important roles in the length and shape of water trees. Namely, the water tree length becomes longer as the number of total zero-crossings increases. Furthermore, among the voltages with the same number of total zero-crossings, the length becomes even longer with a prolonged shape in the direction of electric field as the number of consecutive zero-crossings increases. Effects of superposition of a high-frequency voltage onto a dc voltage are also examined. In this case, the dc voltage seems not to have any influence to the tree growth. By assuming the presence of space charge around the water-tree tip, the effective zero-crossings become only sensitive to the high-frequency component. Therefore, this result also indicates that the number of voltage reversals at the tree tip plays a crucial role in the growth of water trees.

KW - Low density polyethylene

KW - Polymeric insulation

KW - Power cable

KW - Tree length

KW - Water tree

UR - http://www.scopus.com/inward/record.url?scp=6344243611&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=6344243611&partnerID=8YFLogxK

U2 - 10.1109/TDEI.2004.1324360

DO - 10.1109/TDEI.2004.1324360

M3 - Article

VL - 11

SP - 708

EP - 714

JO - IEEE Transactions on Dielectrics and Electrical Insulation

JF - IEEE Transactions on Dielectrics and Electrical Insulation

SN - 1070-9878

IS - 4

ER -