Nyahcas separa berlaku akibat kegagalan dielektrik dibawah tekanan elektrik dan mekanikal dalam sistem penebat. Lama-kelamaan, aktiviti nyahcas separa akan menurunkan tahap penebat bagi sesuatu bahan dan mengakibatkan kegagalan pada akhirnya. Bagi memastikan peralatan voltan tinggi beroperasi dalam tempoh yang lama, nyahcas separa haruslah dipantau bersama isyarat amaran awal untuk pemeriksaan dan penyelenggaraan. Pengukuran nyahcas separa merupakan salah satu cara untuk memantau keadaan sistem penebat. Sistem pengukuran berasaskan alat visual adalah penting supaya isyarat nyahcas ini boleh dikaji dan di analisa dengan mudah. Disebabkan penyelidikan terhadap aktiviti nyahcas bakal dijalankan di makmal kuasa, PPK Elektrik & Elektronik, USM, oleh itu, sistem pengambilan data bagi pengukuran nyahcas perlu dibangunkan kerana ia tiada buat masa ini. Objektif projek ini adalah untuk membangunkan sistem pengambilan data dan juga menganalisa kejadian nyahcas separa dalam udara menggunakan sistem yang telah dibangunkan. Perisian LabVIEW digunakan untuk mereka bentuk sistem pengukuran tersebut. Untuk menganalisa kejadian nyahcas, ujikaji terhadap pengukuran nyahcas dalam udara telah dijalankan dengan mengambil data dalam 300 kitaran voltan gunaan. Keputusan daripada sistem yang dibangunkan menunjukkan bahawa sistem tersebut dapat memaparkan graf voltan yang sama dengan sistem konvensional sekali gus memaparkan graf voltan, arus elektrik nyahcas, pola penyelesaian sudut fasa, mengira bilangan nyahcas yang muncul dan boleh menyimpan data digital nyahcas. Pola ϕ-q-n menunjukkan kejadian nyahcas separa dalam udara muncul pada silang kosong semasa kitaran separuh negatif.
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Partial discharge (PD) occurs as a result of dielectric breakdown under electrical and mechanical stress in insulation system. Over time, PD activity will degrade the insulation level of a material and can cause eventual failure. In order to ensure reliable operation over long term of high voltage equipment, PD should be monitored closely with early warning signal for inspection and maintenance. PD measurement is one of the ways to monitor the condition of insulation system. A measurement system based on visual instrument is important so that PD signal can be studied and analyzed easily. Since the PD research activity is going to be conducted in power laboratory of School of Electrical & Electronic Engineering, USM where the data acquisition system is not yet been developed at this moment, a data acquisition system for PD measurement is necessary to be developed. Thus, the objective of this project is to develop an acquisition system and to analyze the PD occurrence in air using the developed system. LabVIEW software package was used to develop the measurement system. To analyze the PD occurrence, an experimental test of PD measurement in air was conducted by taking the PD data in 300 cycles of applied voltage. Result from the develop acquisition system shows that the system was able to display the graph of applied voltage and PD voltage that is similar to the conventional system. Furthermore, the system can display the waveform of PD current, phase resolve pattern, display measurement data, count the total number of PD pulse appear and can store the digital data of PD in text file (.lvm). The ϕ-q-n pattern shows that the PD occurrence in air was mostly appearing at zero cross during negative half cycle.
Development of data acquisition system for partial discharge measurement using / Norazzuwa Mohamad Razali