Self-tuning regulators for a group of turbogenerators

ABSTRAK With the need to improve the transient stability of existing generating units, multivariable self tuning regulators are proposed in this paper with particular emphasis on their application to large disturbances. This work involves the identification of a group of turbogenerator parameters and the determination of regulator parameters. By simulation and implementation, the use of certain recur¬sive identification techniques shows better parameter tracking, under the transient as well as the dynamic conditions. The use of optimal control or pole-shifting strategy utilizing, respectively, suitable weighting matrices and shifting factor, increasing the flexibility when applied to varying operating conditions encountered in any power system. Comparative results of studies, based on alternate self-tuning regulator algorithm and conventional fixed parameter regulator, show some improvement in the response perform- ed by the adaptive algorithm. Key words: self-tuning, regulato

A New Approach to Optimize Over Current Relay Coordination

A power system can not be separated from interference. Interruptions in  power system may interfere service continuity  and potentially damage equipment due to fault current flow on the line. Therefore, it is needed a protection system that can isolate  disturbed area and can avoid equipment damage. Many relays installed in power protection systems,  and overcurrent relay is an important protective device and widely installed in the power system. This relay is useful to protect equipment from current spikes during interruption or flashover occurs. An electric power protection system can work optimally if there is coordination of installed overcurrent current relay. This research is expected to be useful for optimizing the overcurrent relay coordination protection

PEMETAAN ELEKTROPORASI PADA JARINGAN BIOLOGIS TERPAPAR DENYUT LISTRIK (Electroporation Mapping on Electric Pulse Exposed Biological Tissue)

ABSTRAKElektroporasi jaringan telah dipakai sebagai teknik untuk memudahkan masuknya molekul-molekul ke dalam sel dengan memberikan denyut listrik pada suatu luasan jaringan dalam tubuh. Kesuksesan suatu elektroporasi ditentukan oleh prosedur penerapan, property dan obyek paparan. Tujuan penelitian ini adalah untuk membuat peta elektroporasi pada jaringan biologis tertentu yang terpapar denyut listrik. Jaringan biologis dimodelkan sebagai bahan dielektrika dengan parameter konduktivitas dan permitivitas. Medium dielektrika ini adalah suatu sistem elektrostatik yang memiliki model matematis berbentuk persamaan diferensial parsial. Metode elemen hingga (Finite Element Method, FEM) digunakan sebagai cara untuk penyelesaian masalah. Hasilnya berupa grafik yang memperlihatkan potensial dan medan listrik. Dari simulasi numerik diperoleh hasil bahwa kerapatan medan lebih tinggi pada tempat di sekitar elektroda dan lebih rendah di tempat lainnya yang jauh dari elektroda. Melalui simulasi numeris, suatu peta elektroporasi reversible jaringan biologis yang terpapar denyut medan listrik dapat dibuat dan dapat digunakan sebagai petunjuk bagi praktisi untuk terapi berbasis elektroporasi dengan lebih akurat, berhasil, dan aman.ABSTRACTTissue electroporation is a technique that facilitates the introduction of molecules into cells by applying an electric pulse to certain areas of body. The success of electroporation is determined by procedur of application and the properties of the exposure and object. The aims of this research is to develop an electroporation map on a specific biological tissue being electric pulse exposed. The biological tissue is modeled as dielectric medium with conductivity and permittivity. This medium as a system of electrostatic, modeling of this system leads to get a mathematical model in the form of partial different equation problems. A Finite Element Method (FEM) is used as a tool to solve the problem. The simulation results are graphical presentations showing  the potential dan electric field. It is also shown that the density of the field is higher in the location near electrode and smaller in remote location. A map of electroporation, based on the map of electric field exposure is then can be used as a guidance to practitioner for accurate, successfully and safe electroporation therapy

An Integrated Renewable Energy System for the Supply of Electricity and Hydrogen Energy for Road Transportation Which Minimizes Greenhouse Gas Emissions

Greenhouse gas emissions produced by the energy sector, including the transportation sector, are a problem that must be resolved. One way to solve this problem is to provide energy in the transportation sector in a sustainable way, by using renewable energy. An integrated renewable energy system has been implemented through an optimization model for the supply of electricity and hydrogen energy for road transportation. The proposed model is in the form of mixed-integer linear programming with two objective functions: planning costs and greenhouse gas emissions. The multi-objective model was solved using the linear weighted-sum method. In this article, three scenarios are developed, namely the business-as-usual scenario, the renewable energy scenario, and the renewable energy with energy storage system scenario. The business-as-usual scenario is used to analyze the supply of electricity and hydrogen by prioritizing the objective function of planning costs. The renewable energy scenario prioritizes the objective function of greenhouse gas emissions in the optimization calculation, but without an energy storage system. The optimization calculation with the renewable energy with energy storage system scenario prioritizes the objective function of greenhouse gas emissions by including the energy storage system. The proposed model in a multi-objective form is implemented in a case study of road transportation in the Province of Yogyakarta, Indonesia. The results obtained indicate that the renewable energy with energy storage system scenario produces the lowest emission level of 56.55 Mt CO2 Equivalent, but with the highest planning cost of 192.13 x 109 Billion USD

The Solution for Optimal Power Flow (OPF) Method Using Differential Evolution Algorithm

Optimal Power Flow (OPF) is one of techniques used to optimize the cost of power plant production while maintaining the limit of system reliability. In this paper, the application of differential evolution (DE) method is used to solve the OPF problem with variable control such as the power plant output, bus voltage tension, transformer tap, and injection capacitor. The effectiveness of the method was tested using IEEE 30 buses. The result shows that this method is better than generic algorithm (GA), particle swarm optimized (PSO), fuzzy GA, fuzzy PSO, and bat-algorithm. The simulation of the power plant systems of 500 kV Java-Bali with the proposed method can reduce the total cost of generation by 13.04% compared to the operating data PT. PLN (Persero)

Electricity Demand and Supply Planning Analysis for Sumatera Interconnection System using Integrated Resources Planning Approach

The Sumatra interconnection system, which is the second-largest electricity system in Indonesia, is often experiencing rolling blackouts. That caused by a lack of supply from the power generating system of Sumatra. The Government has planned to develop new power plants through the fast track program (FTP). Until 2015, either power outages and supply shortages are still common. Therefore, an analysis of long-term electricity planning needed to support energy security in Sumatra. The Sumatra electricity system was modelled using integrated resource planning as a framework and the long-range energy alternative planning (LEAP) software as a tool to build and simulate the model. Three groups of scenarios will be compared are the fast track program (FTP) scenario, the biofuel mandatory (BM) scenario and optimization (OPT) scenario. The results show that the implementation of DSM programs through energy conservation scenario would be able to reduce the electricity demand in the future. On the other side, the alternative scenario shows that the electricity deficit could be resolved in 2022, while the optimization scenario shows that energy diversity would resolve the electricity crisis in the Sumatra interconnection system

Optimal Power Flow Using Flower Pollination Algorithm: A Case Study of 500 kV Java-Bali Power System

Flower Pollination Algorithm (FPA) is one of metaheuristic methods that is widely used in optimization problems. This method was inspired by the nature of flower pollination. In this research, FPA is applied to solve Optimal Power Flow (OPF) problems with case study of 500 kV Java-Bali power system in Indonesia. The system consists of 25 bus with 30 lines and 8 generating units. Control variables are generation of active power and voltage magnitude at PV bus and swing bus under several power system constraints. The results show that FPA method is capable of solving OPF problem. This method decreased the generator fuel cost of PT. PLN (Persero), the state-owned company in charge of providing electricity in Indonesia, up to 13.15%

Role Analysis of Distributed Generation Towards Transmission Expansion Planning Using MILP

Electricity demand increase as function of population and economic activity growth. To meet the demand growth, one kind of approaches to expand electrical system is to calculate the need of generating unit and the result will be used to determine the needs of transmission line. In this research, a model was developed with focused on transmission line expansion based on Mix Integer Linear Programming method. The objective function was to minimize overall investment cost for transmission and operating cost of all generating units. The developed model was implemented in 6-bus Garver’s test system. Distributed generation implementation impact is also studied in this study in term of network configuration and overall expansion cost. The results show that distributed generation implementation will differ the network configuration and reduce the overall system cost, with overall system cost with and without distributed generation implementation was $106.4 million and$103.18 million respectively

KECEPATAN PUTARAN DAN FREKUENSI GENERATOR PADA KONDISI BEBAN TIDAK SEIMBANG

Load imbalance caused instantaneous power generator contains components sinusiodal. There is a difference of energy between the stator and rotor always. The energy difference must be balanced by the rotor by means of decrease or increase speed. This gives rise to oscillations in the power angle, frequency and rotation speed of the generator. To determine the oscillation amplitude of the power angle, the instantaneous power generator should be expressed as a function of power angle. This is done by the method of symmetrical components. Angle at steady state power is the amount of power angle caused by the active power and the generator power angle caused by sinusiodal components. The frequency and speed of rotation angle based power generator is known. Oscillation frequency and rotation speed of the generator is affected by the power generated by the negative sequence components, generator inertia constant and damping factor. Keywords: Imbalance, symmetrical components, instantaneous power, power angle, frequency, speed of rotation.  

Studi Stabilitas Pemasangan PSS dengan Memanfaatkan Sinyal Global Berbasis PSO pada Sistem Tenaga Multimesin

This paper presents stability a study on multi-machine power system is equipped with PSS based on global signal as a control signal. Filters in PSS structure is designed based on frequency response, whereas the lead-lag parameters optimized by PSO. The performance of design proposed tested on 3-Machine 4-Bus power system that disturb with load increasing. The eigenvalue and participation factor analysis results show that system with PSS based on coordination between local and global signal have a performance such us damping ratio, settling time and overshoot are better than system with PSS based on local signal only.Keywords : Multi-machine, PSS, global signal, PSO, eigenvalue analysis, participation factor, stability.Abstrak—Paper ini menyajikan studi stabilitas pada sistem tenaga multimesin yang dilengkapi dengan PSS berbasis sinyal global sebagai sinyal kendali. Filter dalam struktur PSS dirancang berdasarkan tanggapan frekuensinya, sedangkan parameter lead-lag dioptimisasi dengan PSO. Unjuk kerja dari rancangan ini diuji pada test system 3-Mesin 4-Bus yang diganggu dengan kenaikan beban. Hasil analisis eigenvalue, participation factor dan simulasi domain waktu menunjukkan bahwa sistem dengan PSS berbasis koordinasi antara sinyal lokal dan sinyal global memiliki unjuk kerja berupa rasio redaman, settling time dan overshoot yang lebih baik dari PSS berbasis sinyal lokal saja.Kata Kunci : Multimesin, PSS, sinyal global, PSO, analisis eigenvalue, participation factor, stabilitas