Margo Pujiantara

Digital overcurrent relay with conventional curve modeling using Levenberg-Marquardt backpropagation

Overcurrent relays (OCRs) play an important role in the protection component that requires high reliability to maintain high security for power systems. Modeling of the OCRcurve using methods like the direct data storage and curve fitting gave only approximate models. Therefore, in this paper proposes modeling of OCRs using Levenberg-Marquardt backpropagation (LMBP). An implementation of OCR in the digital OCR used ARM microcontroller STM32F407VGT6 is to improve performance of the relay significantly. LMBP is developed using different numbers of neurons. The current and opening time of the circuit breaker are used as input and output in the LMBP training. LMBP developed in the OCR curve model using sample data from protection coordination is implemented as real time in Hess Indonesia Corporation. The weights obtained by the LMBP are used to run the LMBP program in the digital OCR. The well known digital OCR product is used for comparison. The results show that this proposed method is accurate and encouraging with percentage error is 0.24% and very promising to be applied in the digital OCR.

Overcurrent relay curve modeling and its application in the real industrial power systems using adaptive neuro fuzzy inference system

Create an accurate model with over-current relays (OCRs) play an important role in the coordination of power system protection. Modeling of the OCR using methods like the direct data storage and software models gave only approximate models. Moreover, modeling based on mathematical models is not appropriate to deal with ill-defined and uncertain systems. Therefore, in this paper proposes modeling of OCRs using adaptive neuro fuzzy inference system (ANFIS). ANFIS is developed using different numbers and types of membership functions (MFs). Each MF is implemented using training and checking data. The load current and time of opening of the circuit breaker are used as input and output in the ANFIS training. ANFIS, which is developed in the OCR curve model using sample data from protection coordination, is implemented in Hess Indonesia Corporation. Different types of MFs are to obtain the optimal design of OCR curves. The result of ANFIS in the OCR curve modeling is accurate and encouraging; thus, the ANFIS model can be used in digital relays and applied successfully in the real systems. In all cases, ANFIS models using 30 Gbell-type MFs yields a very minimum average percentage error of 0.028419 %.

Overcurrent relay curve modeling using adaptive neuro fuzzy inference system

In this paper, modeling of overcurrent relay (OCR) curves using adaptive neuro fuzzy inference system (ANFIS) are proposed. The accurate models of OCR curve with inverse time relay characteristics have an important role for protection coordination of power system. Models of OCR curve are appropriate with IEC standard. This model implements of microcontroller AT mega 128 as digital relay and personal computer as facility to design of OCR curve. ANFIS is developed to OCR curve modeling with different types of membership function and each membership function is trained for 10 iterations. Input for training to OCR curve using the load current and current setting or IL/IS. Time to opening the circuit breaker or TCB is used as output for training of OCR curve. ANFIS is developed using visual basic. The simulation results are compared with different types of membership function to obtain the optimal design of OCR curve. Moreover, the testing results are compared with OCR curve modeling to check validation and accuracy of the proposed model.

Maximum power point tracking algorithm for photovoltaic system under partial shaded condition by means updating β firefly technique

This paper proposes new Simplified Firefly Algorithm (SFA) with an updated β coefficient to maximum power point tracking (MPPT) of photovoltaic system under partial shading condition. The different from standard firefly algorithm is neglected a and y coefficients to simplify an algorithm. The other new feature is updated β coefficient for each iteration step in order to achieve faster convergence. This proposed algorithm is to obtain the optimal solution for MPPT of PV system under three shaded conditions. The simulation results are compared with traditional Perturbation and Observation (P&O) and standard Firefly Algorithm (FA) to verify the proposed method performance. Highest maximum powers and efficiencies are produced by the proposed algorithm. The ripple in steady state condition is also better than P&O and standard FA. The main advantage of proposed algorithm is simpler and faster convergence yet still accurate compared to standard firefly.

Wind farm site selection base on fuzzy analytic hierarchy process method; Case study area Nganjuk

The selection of site wind farm is an important element in building a wind power generation to get a site that is capable of produce maximum energy, economic and environmental agreeable. It is obtained if proposed alternative sites has continuous wind resources, access to the grid, good topography, land costs are cheap, reduce noise blade and available road access. The site proposed of study is Sukomoro, Rejoso, Lengkong, Nganjuk and Pace. It will be decided using Fuzzy Analytic Hierarchy Process(F-AHP) based on multi criteria eg, technical, economic and environment. The decision making process is decided by compare each element of main criteria with each of altenative so that to get a best site, it is best highest weight to recommend. In this study show that, weight of final is resulted by each alternative are Sukomoro is 0.3205, Rejoso is 0.1632, Lengkong is 0.1218, Nganjuk is 0.3095 and Pace is 0.0602. Based on testing, Sukomoro to get highest weight so that it is recommended for use by governments and companies electricity as a reference in policy formulation and calculate cost of electricity.

Combining Simplified Firefly and modified P&O algorithm for Maximum Power Point Tracking of photovoltaic system under Partial Shading Condition

This paper proposes the combination of firefly and P&O algorithm to get both of its benefit. Simplified firefly algorithm used for escaping partial shading multi peaks condition due to Partial Shading Condition (PSC). When it goes yet to converge, the algorithm used is switched to faster modified P&O algorithm. This proposed algorithm is to obtain the optimal solution for Maximum Power-Point Tracking (MPPT) of Photovoltaic (PV) system under three shaded conditions. The simulation results are compared with traditional Perturbation and Observation (P&O) and Simplified Firefly Algorithm (SFA) to verify the proposed method performance. The main advantage of proposed algorithm is faster convergence and tracking speed compared to its previous method that is Simplified Firefly Algorithm (SFA).

The modeling of directional overcurrent relay in loop system using cascade forward neural network

The problems arising in loop electrical network system is a relay setting that follows changes in the system such as power source operation, regular maintenance and damage to powers source. To obtain an adaptive relay which is capable of following the changes in the network system, this paper is proposes the modeling of the coordination of the power system network with the cascade forward neural network (CFNN) by simulating three power sources, fifteen protection relays, six buses, and three loads. CFNN applied in the directional overcurrent relay (DOCR) curve model using sample data from protection coordination in loop electrical network system. On the modeling process by comparing some number of neurons and learning rate to get the best accuracy and time speed with four combination input and two outputs. The results of modeling relay using CFNN method showed mean square error of 3,24e-06 with a current contribution of 95% and mean square error of 2,10e-03 with a current contribution of 105% and from modeling is very accurate and can be applied to digital overcurrent relay.

Analisis Implementasi Saturated Iron – Core Superconducting Fault Current Limiter pada Jaring Distribusi PT. PERTAMINA RU V BALIKPAPAN.

Pada studi ini akan dilakukan analisis hubung singkat pada sistem distribusi PT. PERTAMINA RU V. Analisis hubung singkat dilakukan pada bus utama PT. PERTAMINA RU V dengan rating 6,6 kV dan melihat pada bus mana yang tidak mampu menahan besarnya arus gangguan karena adanya retrofit generator STG I-4 yang terhubung pada sistem kelistrikan PT. PERTAMINA RU V. Saat terjadi gangguan hubung singkat 3 fasa peak pada bus 2HT dan 3HT, rating bracing peak pada bus sebesar 78,75 kA tidak mampu menahan arus gangguan sebesar 84,72 kA. Agar tidak terjadi kerusakan pada bus tersebut, maka diperlukan sebuah device pembatas arus gangguan yaitu Saturated Iron – Core Superconducting Fault Current Limiter (SISFCL). SISFCL dipasang pada satu incoming yang terhubung ke bus 2HT dimana pada incoming ini menyumbang arus kontribusi. Setelah dipasang SISFCL, nilai arus gangguan pada bus 2HT dan 3HT berkurang dari 84,72 kA menjadi 73,12 kA. Arus gangguan pada incoming yang dipasang SISFCL juga akan berkurang sehingga setting koordinasi proteksi untuk rele arus lebih juga akan berubah untuk itu diperlukan setting ulang pada beberapa rele. Setting ulang rele ditunjukkan pada kurva TCC ( Time Current Curve).

Analisa Arc Flash pada Sistem Kelistrikan Di PT. Asahimas Flat Glass Tbk. Sidoarjo

Arc Flash adalah total energi yang dilepaskan ketika terjadi gangguan hubung singkat. Energi akan dilepaskan melalui udara mengalir ke fasa lain, netral atau mengalir ke tanah. Ketika pekerja yang tidak dilengkapi alat pelindung diri berada di dekat dengan Arc Flash, maka akan menyebabkan cedera serius dan bahkan kematian. Berdasarkan standar IEEE 1584-2002 yang mengatur tentang analisa bahaya busur api pada sistem tegangan rendah dan menengah, pengguna dapat dengan mudah menentukan batas keamanan untuk para pekerja. Menurut rekomendasi standar IEEE perhitungan arus hubung singkat selalu memperhatikan kontribusi arus gangguan dari generator, motor induksi dan sinkron. Besar kecilnya energi arc flash dapat ditentukan dari beberapa sudut pandang. Diantaranya ialah nilai energi arc flash akan besar apabila dihitung dengan menggunakan arus bolted three phase fault, sedangkan dari sudut arc clearing time yang didapat dari waktu dimana arus gangguan saat itu terjadi akan menghasilkan nilai energi busur api yang lebih rendah. Untuk mengurangi atau menurunkan nilai dari arc clearing time ini banyak metode yang digunakan, diantaranya adalah melakukan resetting koordinasi proteksinya seperti yang dilakukan dalam tugas akhir ini. Untuk hasil yang didapat pada tugas akhir ini adalah pada tipikal 1 nilai insiden energi tertinggi 31.576 cal/cm2 turun menjadi 10.764 cal/cm2 , pada tipikal 2 nilai insiden energi tertinggi 30.387 cal/cm2 turun menjadi 16.8 cal/cm2, pada tipikal 3 nilai insiden energi nya mengalami penurunan yaitu dari 30.513 cal/cm2 menjadi 15.94 cal/cm2.

Controlled bidirectional converter using PID for charging battery in the stand-alone wind turbine system with Modified P&O to obtain MPPT

The main problem which often occurs in wind turbine systems is getting the maximum power output and maintaining the DC link voltage at a constant value through wind fluctuation. This paper proposed to maintain the DC link voltage during stand-alone condition, it takes a battery as energy storage with a bidirectional buck-boost converter to regulate charging and discharging mode, alternately. Control of bidirectional DC-DC converter using PID controller. Meanwhile, Modified Perturbation and Observation algorithm to set switching of quadratic boost converter for obtaining the Maximum Power Point (MPP) of the wind energy system. The results of this research, the efficiency of wind turbine system can be improved up to 98,176% using the modified P&O.