The coefficients of the TD models in pu for 12, 24 and pulse arrangements are given in Appendix B. The time domain models are derived using the equivalent circuit of Figure 6.
Received Feb 13; Accepted Jun The diminution of SSR is achieved by the raising of network damping at those frequencies which are proximate to the torsional mode frequency of the turbine-generator shaft. The increase of network damping is obtained with the injection of subsynchronous frequency component of current and both current and voltage into the line.
The subsynchronous component of current and voltage are derived from the measured signal of the system and further the same amount of shunt current is injected with STATCOM and simultaneous injection of current and voltage with UPFC into the transmission line to make the subsynchronous current to zero which is the prime source of turbine shaft oscillations.
The IEEE first benchmark model has adopted for analyze the effectiveness and speed of the proposed control scheme using MATLAB-Simulink and the corresponding results illustrates the precision and robustness of the proposed controller. Fractional-order PI controller, STATCOM, Torque amplification, Voltage source converter, UPFC Background Series capacitor compensation has been broadly employed in Power system to cancel a portion of reactance of the line impedance to increment the power transfer capability of long high voltage HV and extra high voltage EHV transmission lines further load sharing among parallel lines and boosts the steady state and transient stability limits Anderson et al.
However, the addition of capacitive compensation in series can cause a new difficulty of turbine-generator shaft oscillations with below the system frequency due to Subsynchronous Resonance SSR. The subsynchronous oscillations can be excited during the fault or disturbance in the transmission line with series capacitors, when the normal system frequency matches with the complement of any of the mode frequency of the shaft system Kundur ; Padiyar The selection of controller is depends on extraction of the subsynchronous frequency components with high speed and accuracy.
From the knowledge of subsynchronous frequency component of current and voltage a proper protection system is designed to avoid shaft breakage due to SSR Bongiorno et al. The parameters of SSDC are tuned to get good performance to provide damping positive in the range of torsional mode frequencies.
The injection of subsynchronous frequency component of voltage in series with subsynchronous current suppresser using SSSC based on the knowledge of subsynchronous current to damp out the SSR is proposed in Panda et al.
Fractional-order PI controllers having larger stability limit with larger phase value as compared to PI controller. Moreover, the Fractional-order PI controllers FOPI exhibits a less negative phase than the PI controller and it implies that more robustness in the sense of stability to changes in the overall system parameters.
The paper is organized in four sections. The generated voltage and the grid current are expressed as vs and i respectively. The main principle of SSR mitigation with classical control scheme is to restore the voltage generated of frequency of fundamental by the added bank of fixed capacitor by injecting a voltage of like magnitude with series converter Bongiorno et al.
With the injection of shunt current by STATCOM and both current and voltage into the line by UPFC eliminates the capacitive reactance of the capacitor bank and further shifts the system resonance electricalthus avoids the problem of subsynchronous resonance.
Several publications have described the capability of used control method Bongiorno et al. The analytical procedure for realization of current and voltage components of subsynchronous frequency from the signal which is measured from the transmission line is proposed as fallows.Comparison of ANFIS Based SSSC, STATCOM and UPFC Controllers for Transient Stability Improvement Ali Shishebori 1, Forough Taki 2, Saeed Abazari 3, Gholamreza Arab Markadeh 4.
73 CHAPTER 4 MODELLING OF UPFC AND STATCOM FORMULTIMACHINE SYSTEM STABILITY INTRODUCTION Stability is a condition . Power Flow Control using UPFC Device Gehan Gouda.M.
A. 1, Abdel-Moamen M. A. and Gaber Shabib.
2 Newton- Raphson, SSSC, TCSC and STATCOM. I. INTRODUCTION The rapid development of power electronics has made it possible to design power electronic equipment of high rating Representation of series converter model of UPFC.
disconnecting the wind turbine from the grid [6–8]. It is necessary to examine the responses of SCIG wind farm during the faults and possible impacts on the system stability. The purpose of this paper is to study the impact of unified power flow controller (UPFC) witch is one of FACTS devices,.a combination of static synchronous compensator (STATCOM) and a static.
Here wind farm is included in UPFC compensated transmission line. The fault detection analysis & fault time is computed using the DWT (Discrete wavelet transform) approach. “Mathematical models for current, voltage, and coupling capacitor voltage transformers”, IEEE Trans.
S.C Swain “A DWT based differential relaying scheme of a.