KARAKTERISTIK PETIR INDONESIA DAN PENGGUNAANNYA DALAM EVALUASI UNJUK KERJA SALURAN UDARA 150 KV SAAT TERJADI SAMBARAN PETIR

Berdasarkan data historis, gangguan saluran transmisi udara di Indonesia mayoritas disebabkan oleh sambaran petir; hal tersebut mendorong PT PLN (Persero) sebagai perusahaan listrik milik negara untuk mengevaluasi unjuk kerja saluran udara terhadap sambaran petir. Pada makalah ini disajikan evaluasi karakterisasi petir menggunakan rekam data sistem deteksi petir/LDS (studi kasus untuk Jawa Barat) meliputi: jumlah sambaran, persentase polaritas, nilai modus arus puncak, persentase kejadian kumulatif, serta peta kerapatan petir. Evaluasi unjuk kerja saluran dilakukan melalui 1) simulasi tegangan lebih menggunakan perangkat lunak transient pada pemodelan saluran 150 kV untuk mengetahui korelasi arus puncak petir terhadap kenaikan tegangan pada insulator saat terjadi sambaran petir dan 2) evaluasi sudut lindung menggunakan Electro Geo-metric Model (EGM). Berdasarkan pengolahan data tahun 2018-2020, terdapat fluktuasi total kejadian petir per tahun dimana 84,63% (σ= 1,71) dari kejadian merupakan petir polaritas negatif. Modus nilai arus puncak petir adalah 12,33 kA (σ= 1,52), sementara persentase kejadian kumulatif memiliki knee point pada nilai 40 kA. Pola kerapatan petir tertinggi tidak mengalami perbedaan signifikan selama periode pengamatan dan bulan ke-7 merupakan periode dengan kejadian petir terendah. Hasil simulasi sambaran petir 40 kA pada kawat pembumiaan menunjukkan bahwa insulator mengalami kenaikan tegangan hingga 1083 kV; hal tersebut mendekati nilai Basic Impulse Insulation Level (BIL) dari insulator. Desain sudut lindung mampu mencegah shielding failure untuk arus petir ≥11 kA; meskipun demikian, perlu dicatat bahwa shielding failure akibat petir 10 kA menyebabkan kenaikan tegangan insulator melebihi nilai BIL. Peningkatan unjuk kerja saluran transmisi 150 kV tersebut dapat dilakukan dengan didasari oleh pertimbangan risk, cost dan benefit yang komprehensif.

The Calculation Method of Shielding Failure Trip Rate of UHV Transmission Lines in Mountainous Areas

Since the second industrial revolution, electric energy has always been the most important and indispensable clean energy in the international community. As a kind of transmission technology with small loss ratio and long transmission distance, UHV transmission is widely used and vigorously promoted in the world. However, UHV transmission lines are often assumed to be vulnerable to thunderstorm discharge in some harsh geographical environment. In order to improve the calculation accuracy of line shielding failure rate, an improved electrical geometric model is proposed to study the shielding failure characteristics of transmission lines under complex mountainous areas, and various typical characteristics including mountain tops, valleys, slopes, climbing, and crossing trenches are summarized.

Analysis of Lightning Performance on 345 kV Transmission Lines Using Python Programming

One of main causes of interruption of electrical power supply is the lightning strike on overhead power transmission lines. The lightning performance of transmission line can be determined by value of shielding failure flashover rate (SFFOR) and back flashover rate (BFOR). The object of this study is to create a computer application to compute lightning performance on the transmission lines using Python programming. Pythons package tkinter used for program interface window. Application programming is done by using the concept of object-oriented programming (OOP) using Pythons keyword class. Validation shows that the application has applied the method correctly with a percentage error 0 % for SFFOR and 3.14 % for BFOR. The application can do analysis on the factors that affecting SFFOR and BFOR such as the effect of thunder day, tower foot resistance, and number of isolator disk. The results obtained in this study is computer application that can perform lightning performance analysis and analysis of factors that can affect it, such as thunder day, tower foot resistance and the number of isolator disk.

A Methodology for Optimal Design of Transmission Lines to Protection against Lightning Surges in Presence of Arresters

In this paper, a methodology for determination of the optimal value of protection design parameters, i.e. tower footing resistance, insulation strength, and surge arresters’ rating in the planning stage of transmission lines (TLs) is presented. This method calculates the shielding failure flashover rate (SFFOR) of TLs, based on Electro-geometric model (EGM) of TLs, and the back flashover rate (BFR) of TLs, based on the Monte Carlo method, in which the accuracy of the proposed methodology has been verified by comparing the resultant results with those obtained with the use of the IEEE FLASH program. The proposed method can be directly used to achieve the minimum lightning flashover rate (LFOR) of TLs by the minimum investment cost. Also, it can be used, indirectly, for determination of the appropriate value of the footing resistance, insulation strength and arresters’ rating to satisfy any target number of LFOR that might be specified by the utilities or standards.