Shafting Torsional Vibration Analysis of 1000 MW Unit under Electrical Short-Circuit Fault

Taking a 1000 MW turbine generator as the research object, the short-circuit fault in electrical disturbance is analyzed. Since it is very difficult to carry out fault analysis experiments and research on actual systems, simulation analysis is one of the more effective means of electrical fault diagnosis; the simulation’s results approach the actual behavior of the system and are ideal tools for power system analysis, and can provide an empirical basis for practical applications. The short-circuit fault model of the SIMULINK power system is built to analyze the two types of faults of generator terminals short-circuit and power grid short-circuit. The impact load spectrum, fault current and speed fluctuation between low-voltage rotors were extracted and analyzed. The conclusion is that the impact value of electromagnetic torque at the generator terminal is greater than that on the power grid side. The impact value of a two-phase short-circuit at the generator terminal is the largest, and that of a three-phase short-circuit on the power grid side is the smallest. The transient impulse current of a three-phase short-circuit at any fault point is greater than that of a two-phase short-circuit; the impulse current of the grid side short-circuit is much greater than that of the generator terminal short-circuit; the speed fluctuation and fluctuation difference caused by the three-phase short-circuit in the grid side are the largest. The alternating frequency of the transient electromagnetic force of the four kinds of faults avoids the natural frequency of the torsional vibration of the shaft system, and the torsional resonance of the shaft system in the time domain of the short-circuit fault will not appear. However, after the fault is removed, the residual small fluctuation torque in the system has a potential impact on the rotor system. This research shows an analysis of the structural integrity and safe operation of turbine generator units after a short-circuit fault, which can not only be applied to engineering practice, but also provide a theoretical basis for subsequent research.

Simulasi ETAP untuk Evaluasi Proteksi Gangguan Tegangan Lebih Generator Unit 3 PLTP Kamojang

AbstrakPada penelitian ini dilakukan evaluasi proteksi gangguan tegangan lebih pada generator Unit 3 PLTP Kamojang yang diproteksi oleh sebuah relay tegangan lebih menggunakan simulasi pada software ETAP. Simulasi dilakukan untuk melihat bagaimana cara kerja relay tegangan lebih dan bentuk tegangan lebih yang terjadi pada terminal generator. Skenario simulasi yang digunakan yaitu melakukan pelepasan beban 50,7 MW dan relay yang digunakan dalam simulasi berfungsi untuk menyalakan alarm saat terjadi tegangan lebih. Hasil simulasi memperlihatkan bahwa pada saat terjadi pelepasan beban, relay tegangan lebih menyalakan alarm 1,1 detik setelah membaca tegangan naik hingga 13 kV atau sebesar 110% dari tegangan nominalnya, kemudian tegangan terminal generator naik hingga 13,2 kV hingga kembali ke kondisi steady state 5 detik setelah terjadi kenaikkan tegangan. Hasil simulasi tersebut menunjukkan bahwa relay tegangan lebih yang terpasang pada terminal generator Unit 3 bekerja sesuai dengan fungsinya yaitu untuk memberikan alarm ketika tegangan lebih terjadi.Kata kunci: pelepasan beban, proteksi generator, relay proteksi, simulasi generator, tegangan lebihAbstractThis study evaluates overvoltage fault protection on the generator Unit 3 PLTP Kamojang which is protected by an overvoltage relay using simulation on ETAP software. Simulations are carried out to see how the overvoltage relay works and the form of overvoltage that occurs at the generator terminals. The scenario used is by do a load shedding of 53,3MW, the relay used in this simulation has a function to turn on the alarm when overvoltage occurs. The results show that when a load shedding occurs, the overvoltage relay turns on the alarm 1,1 seconds after reading the voltage up to 13 kV or 110% of the nominal voltage, then the generator terminal voltage rises to 13.2 kV until it returns to steady state 5 seconds after the voltage increase. The simulation results indicate that the overvoltage relay installed at the generator terminal Unit 3 works according to its function, namely to provide a warning when an overvoltage occurs.Keywords: generator protection, load shedding, overvoltage, protection relay, generator simulation

Synchronous Generator Excitation Control Based on Model Predictive Control

This thesis research has designed and developed an optimal predictive excitation control, named the Model Predictive Excitation Control (MPEC), for utility generators. Four significant results are achieved: First, the MPEC has been designed and has significantly improved the classical model predictive control and is much simpler and computationally efficient. Second, the MPEC simulation program and results have been accomplished, and study cases have demonstrated the effectiveness of the MPEC. Third, the Modified classical model predictive control procedure has been formulated to correct a timing error such that the controlling input for the present time is re-written as that for the next step. Fourth, the MPEC optimization formulation and procedure has been developed for the generator control with only two substation-ready-available measurements which are the generator terminal voltage and speed.

Synchronous Generator Excitation Control Based on Model Predictive Control

This thesis research has designed and developed an optimal predictive excitation control, named the Model Predictive Excitation Control (MPEC), for utility generators. Four significant results are achieved: First, the MPEC has been designed and has significantly improved the classical model predictive control and is much simpler and computationally efficient. Second, the MPEC simulation program and results have been accomplished, and study cases have demonstrated the effectiveness of the MPEC. Third, the Modified classical model predictive control procedure has been formulated to correct a timing error such that the controlling input for the present time is re-written as that for the next step. Fourth, the MPEC optimization formulation and procedure has been developed for the generator control with only two substation-ready-available measurements which are the generator terminal voltage and speed.

High Voltage Ride through Strategy of Wind Farm Considering Generator Terminal Voltage Distribution

When wind power is transmitted via high-voltage direct current (HVDC), the problem of high-voltage ride-through (HVRT), caused by direct-current (DC) blocking must be seriously taken into account. All the wind turbines in a wind farm are usually equivalent to a single turbine in the existing research on HVRT, which ignores the generator terminal voltage distribution in a wind farm. In view of the fact that the severity of fault voltage felt by each wind turbine in the field is different, an improved HVRT strategy considering voltage distribution is proposed in this article. First, this article analyzes the mechanism of voltage swell failure caused by DC blocking, and the characteristics of the generator terminal voltage distribution in wind farms. Second, the reactive power characteristic equations of the synchronous condenser and the doubly-fed induction generator (DFIG) are derived. Third, based on the extraction of the key node voltage, this article takes the key node voltage as the compensation target, and put forwards a HVRT strategy combining the synchronous condenser and wind turbine. Finally, the simulation is carried out to demonstrate the effectiveness of the proposed strategy in improving the HVRT capability of all wind turbines.

Kontrol Tegangan Self-Excited Induction Generator dengan Electronic Load Controller Terkontrol PID-GA

Induction generator operation requires reactive power with external contactor. One of induction generator types, SEIG reactive power supplied by capacitor bank connected to generator terminal. SEIG is alternative energy conversion in small area or rural, SEIG has the main disadvantage of poor voltage regulation under various load conditions. ELC combine PID control which is optimized using Genetic Algorithm in order to maintain the stability of the voltage when the load varies. The result shows the SEIG system using ELC with PID-GA control worked to stable voltage in accordance with the standard with voltage tolerance of 10% when load change. The addition of GA to determine the value of the PID parameter where response system better with difference overshoot value start is 70.48%, when decrease load in 5 second by 44.3% and in the 10 second when increase load of 2 kW is 5.96% compared system with PID control without GA optimization.

Enhancement of Energy Efficiency of Hydro Turbine Generators by Energy Conservation Techniques

This paper describes the results of enhancing energy efficiency of hydro turbines by implementing the energy conservation measures for hydro turbine generators. The procedure for evaluating the on-line performance of generators is discussed. The energy saving in generators by maintaining optimum generator terminal voltage, by reducing the stator winding temperature by improving the performance of coolers and reducing the excitation loss by appropriate tuning of excitation system are enumerated in details with case studies. The implementation of energy conservation measures have a techno-economic feasibility with a payback period of 1 to 5 years.

Development of Intelligent AVR for Synchronous Generator

The major part of an automatic voltage regulator (AVR) is to normalise the terminal voltage of synchronous generator. The structure modelled contains of the amplifier and generator. The AVR organisms are recycled usually in exciter control system. The part of an AVR is to grip the generator terminal voltage constant below standard operating surroundings at different load levels. The AVR loop of excitation mechanism preparation works terminal voltage error for adjusting the field voltage so as to mechanism the terminal voltage. The basic mechanisms of an exciter control system arrangement comprises of four leading components, namely amplifier, sensor, exciter and generator. The generator and amortisseurs systems state matrix are included, the system equations developed in that model includes one d-axis amortisseurs and two q-axis amortisseurs. This exertion targets to improve a simulation on steady state analysis of a power system with a controller established on fuzzy logic to maintain the terminal voltage.

Loss of Excitation Protection of Medium Voltage Hydro Generators Using Adaptive Neuro Fuzzy Inference System

This chapter presents a new method for loss of excitation (LOE) faults detection in hydro-generators using adaptive neuro fuzzy inference system (ANFIS). The investigations were done under a complete loss of excitation conditions, and a partial loss of excitation conditions in different generator loading conditions. In this chapter, four different techniques are discussed according to the type of inputs to the proposed ANFIS unit, the generator terminal impedance measurements (R and X) and the generator terminal voltage and phase current (Vtrms and Ia), the positive sequence components of the generator terminal voltage magnitude, phase current magnitude and angle (│V+ve│, │I+ve│ and ∟I+ve) in addition to the stator current 3rd harmonics components (magnitudes and angles). The proposed techniques' results are compared with each other and are compared with the conventional distance relay response in addition to other techniques. The promising obtained results show that the proposed technique is efficient.