Papers by Keyword: Synchronous Generator

Abstract: The study explores the creation of a simulator for addressing the problem of predicting response of Nigeria’s Kainji’s Hydro Power Plant (KHPP) to system load variations and to determine parameters for stable operation. A virtual KHPP Simulation Model was designed and created using MatLab/Simulink software. The components of the HSS designed and incorporated in the virtual simulator include models of all eight (8) generating units (GUs). Each GU model consists of the Hydraulic Turbine Governor (PID), synchronous generator and an excitation system. The simulator was tested with steady state stability (SSS) and transient stability (TS) disturbances to obtain response values of system operating state parameters. The tests include a variable load increase, and three-phase short circuit fault for a duration of 0.2 s. The SSS limits established are the following: active load – 810 MW, load angle – 85⁰, terminal voltage 0.68 pu, rotor speed 1.08 pu, excitation voltage 1.55 pu, and stator current 7.5 pu. TS limits established are load angle (170⁰), terminal voltage (0.60 pu), rotor speed (1.05) pu, excitation voltage (1.25 pu), stator current (7.1 pu), and critical clearing time (0.2s). Clearing time should be set at 0.2s to prevent KHPP and connected system’s instability.

Abstract: This paper focuses on the fault blocking analysis and operational issues associated with MTDC systems incorporated in an AC network. The dynamic modelling of a line-commutated converter based bipolar multi-terminal direct current (LCC MTDC) system are shown, and the dynamic response of the converter during a DC converter fault is discussed. The converter controller design for both rectifiers and the inverters system was modelled for a realistic active power and extinction angle (γ) control with consideration to the VI characteristics of all the converter stations. An overall power controller was modelled for both converter pole. Two operational scenarios of converter fault were simulated using PSCAD EMTDC. The converter firing angle and extinction angle, as well as the voltage-dependent current order limiter, was monitored and plotted on a graph. Results show that the MTDC link became unstable during the full deblocking stage with a continuous occurrence of commutation failure. Furthermore, the results presented in this paper show that during partial converter de-blocking showed a favourable performance, as the power system remains stable and commutation failure of the MTDC system is prevented.

Abstract: This paper presents a solution for the real power control, generated by a synchronous generator belonging to a small hydroelectric power plant. The proposed control system is based on the simple feedback structure which contains also, a frequency correction loop. The mathematical models of all the elements from the control structure are detailed. Also, starting from these models, the real power controller (of Proportional – Integral – Derivative type) tuning procedure is presented. In the end of the paper, the simulations results of the control system are presented highlighting the obtained control performances. The proposed solution is a general one and it can be adapted with relative minor changes to any hydroelectric power plant.

Abstract: The models of the synchronous generator for calculating the steady-state and transient regimes including the transients of stator windings of generator without damper windings have been presented. The ability to use different mathematical approximations of the generator models depending on the spatial distance of the disturbance point has been shown. The examples of the generator models without damper windings which is equipped with an automatic stabilizer have been given. To determine the currents and voltages as functions of time the state-space technique and Park – Gorev transformation have been used. Solutions are obtained by means of the program called integrated environment MathCAD Runge-Kutta method.It is possible to use these models in networks containing synchronous generators and also for the design of objects containing generators.

Abstract: The paper describes the determination method of quasi-reactive power for synchronous generator turn-to-turn short circuit diagnostics. A proposed method allows to determine the relation between the exciting current and quasi-reactive power at the generator leading to a high probability. This relation is the basis of the determination method of turn-to-turn short circuit availability and its severity.

Abstract: STATCOM and synchronous generator are considered as measures of providing dynamic reactive power to power grid. Based on a real regional power grid, ability of voltage support between STATCOM and generator are compared through digital simulations. The results shows that STATCOM always provides additional reactive power to persist voltage collapse, while ability of generator reactive power are restricted by terminal voltage under faults.

Abstract: In order to realize the solar photovoltaic (PV) system connecting with grid friendly, a PV system with voltage-controlled inverter based on virtual synchronous generator (SG) is presented. This kind of system has features of SG, which supply the virtual moment of inertia to grid. The mathematical model of PV and virtual SG is built, and the control strategy of the maximum power point tracking (MPPT) is also studied in the paper. Simulation model of the grid-connected PV power system is built on Matlab/Simulink. Finally, correctness and feasibility of this system are verified by simulation results.

Abstract: In paper considers the principle of the control system power grid in the form of multilevel system consisting of a system of planning and allocation of management tasks, control system of the segments the grid, the local management system of elements of the grid. The paper shows the principle of operation of the upper and lower levels of the system, an example of a calculation for a segment of the grid, for which the system provides a balance of power capacities.

Abstract: When synchronous generator operates steadily, the slip remains essentially unchanged, and the traditional first-order mathematical model can be used to analyze its operating procedures. But when it occurs asynchronously failure, the traditional model of a first-order mathematical operation can no longer be used accurately to analyze its state. This paper establishes time-varying parameter model considering the rotor eddy based on mutual leakage field winding and straight shaft damper windings resistance, and uses simulation analysis and comparison of experimental verification methods to verify the correctness of the model for synchronous generator asynchronous operation, which provides a theoretical basis.

Abstract: Synchronous generator excitation failure can lead to loss of field, after field loss will lead to the generator lose synchronization. The slip is occurred on the rotor, the generator will absorb a large number of reactive powers from power grid. System voltage is reduced, may make some adjacent point voltage is lower than the allowable values, break the stable operation status between load and power supply, and even make the system voltage collapse; The increased stator current may cause other generator, transformer and circuit overload, make backup protection action, and increase the fault extent; From the perspective of the experimental, this article analyzes the change of stator current in the process of QFQS – 200 synchronous generator loss of field, which provides data for the practical operation of the generator.