Sistem kuasa dengan penghantaran voltan tinggi diperlukan untuk menjana, menghantar dan mengedarkan kuasa elektrik di seluruh rantau. Kabel adalah salah satu peralatan yang biasanya digunakan kerana ia boleh menghantar elektrik. Terdapat banyak jenis kabel yang ada bergantung pada tujuannya. Kabel dengan keadaan operasi yang baik dapat mengurangkan risiko sekitar kabel dalam memindahkan kuasa maksimum kepada pelanggan. Oleh itu, prestasi kabel penebat boleh terjejas apabila aktiviti Pelepasan Separa (PD) berlaku kerana kehadiran lompang. Penebat memainkan peranan penting dalam peralatan voltan tinggi. Kerosakan pecahan penebat dapat menyebabkan kegagalan bencana untuk keseluruhan sistem. Dalam kerja ini, model kabel kuasa bertebat 3-fasa 3-fasa Cross-linked Polyethylene (XLPE) simulasi telah dibangunkan dengan menggunakan COMSOL Multiphysics untuk mengkaji kesan rongga udara dan kelembapan pada pengagihan medan elektrik penebat kabel XLPE. Kesan saiz dan lokasi rongga dalam penebat kabel XLPE disiasat. Tiga syarat saiz rongga; 0.5mm, 1.0mm dan 2.0mm digunakan dengan pelbagai lokasi rongga udara yang berhampiran konduktor, tengah penebat dan jauh dari konduktor. Sementara itu, lokasi rongga kelembapan adalah berhampiran penebat, tengah penebat dan konduktor dekat. Hasilnya, medan elektrik yang lebih tinggi di sempadan pertama rongga udara berhampiran konduktor ialah 4.5MV/m berbanding rongga yang terletak di tengah penebat dan jauh dari konduktor. Pembesaran saiz rongga kelembapan dari 0.5mm hingga 2.0mm meningkatkan medan elektrik di rongga kelembapan sempadan pertama berhampiran konduktor dari 0.9112MV/m hingga 1.022MV/m. Rongga udara mempunyai pengagihan medan elektrik yang lebih tinggi di pusat rongga berbanding dengan rongga kelembapan. Saiz 0.5mm rongga udara mempunyai medan elektrik yang lebih tinggi di pusat rongga yang terletak berhampiran konduktor 5.10MV/m berbanding dengan tengah penebat dan jauh dari konduktor. Pembesaran saiz kelembapan dan rongga udara dari 0.5mm hingga 2.0mm berhampiran konduktor, medan elektrik di pusat rongga udara sedikit berkurangan dari 5.10MV/m hingga 4.252MV/m tetapi medan elektrik di pusat kelembapan rongga sedikit meningkat dari 0.35MV/m ke 0.41MV/m. Rongga kelembapan mempunyai medan elektrik yang lebih tinggi pada batas kedua rongga berbanding rongga udara. Medan elektrik di sempadan kedua rongga udara berhampiran konduktor sedikit menurun dari 5.109MV/m hingga 3.912MV/m. Untuk rongga kelembapan, medan elektrik di sempadan kedua rongga berhampiran konduktor berkurangan dari 7.812MV/m hingga 7.77MV/m.
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Power system with high voltage transmission is necessary to generate, transmit and distribute electrical power throughout region. Cable is one of the equipment that usually used as it can transmit electricity. There are many types of cable available depending on its purpose. Cable with good operating condition can reduce the risk around the cable in transferring of maximum power to customer. Thus, performance of the insulation cable can be affected when the Partial discharge (PD) activities is occurred due to the presence of voids. Insulators play an important role in high voltage equipment. Fatal breakdown of insulator could cause catastrophic failure for overall system. In this work, a simulated 3-phase 3-core Cross-linked Polyethylene (XLPE) insulated power cable model has developed by using COMSOL Multiphysics to study the effect of air and moisture cavities on electric field distribution of XLPE cable insulation. The effect of the size and location of the cavities in the XLPE cable insulation are investigated. Three conditions of size of the cavities; 0.5mm, 1.0mm and 2.0mm are used with various location of the air cavities which are near conductor, middle of insulation and far from conductor. While, the location of the moisture cavities are near insulation, middle of insulation and near conductor. As the result, the higher electric field at first boundary of the air cavity near to conductor is 4.5MV/m compared to cavity located in middle of insulator and far from conductor. The enlargement in size of moisture cavity from 0.5mm to 2.0mm is increased the electric field at the first boundary moisture cavity near to conductor from 0.9112MV/m to 1.022MV/m. The air cavity has higher electric field distribution at the centre of cavity compared to the moisture cavity. An 0.5mm size of air cavity has higher electric field at the centre of cavity located near to conductor of 5.10MV/m compared to the middle of insulator and far from conductor. The enlargement in size of moisture and air cavities from 0.5mm to 2.0mm near to conductor, the electric field at the centre of air cavity is slightly decreased from 5.10MV/m to 4.252MV/m but the electric field at the centre of moisture cavity is slightly increased from 0.35MV/m to 0.41MV/m. The moisture cavity has higher electric field at the second boundary of cavity compared to air cavity. The electric field at the second boundary of air cavity near to conductor is slightly decreased from 5.109MV/m to 3.912MV/m. For moisture cavity, the electric field at the second boundary of cavity near to conductor is decreased from 7.812MV/m to 7.77MV/m.
Electric field distribution of xlpe insulated power cable under presence of moisture and air cavities / Nurhayati Latif