Influence of large-scale PV on voltage stability of sub-transmission system

Voltage instability is considered as one of the main threats to secure operation of power systems around the world. Grid connected renewable energy-based generation are deploying in recent years for many economic and environmental reasons. This type of generation could have significant impact on power system voltage stability given the nature of the primary source for generation and the technology used for energy conversion. This paper presents the results of an investigation of static voltage stability in heavily stressed IEEE-14 bus test system with large-scale PV integration. The study focused on the impact of large-scale PV penetrations and dynamic VAr placements on voltage stability of the sub-transmission system. For this study, the test system loads are modeled as the summer peak load of a realistic system. The comparison of STATCOM and SVC performance with large-scale PV is also discussed

A Simultaneous Perturbation Stochastic Approximation (SPSA)-Based Model Approximation and its Application for Power System Stabilizers

Abstract: This paper presents an intelligent model; named as free model, approach for a closedloop system identification using input and output data and its application to design a power system stabilizer (PSS). The free model concept is introduced as an alternative intelligent system technique to design a controller for such dynamic system, which is complex, difficult to know, or unknown, with input and output data only, and it does not require the detail knowledge of mathematical model for the system. In the free model, the data used has incremental forms using backward difference operators. The parameters of the free model can be obtained by simultaneous perturbation stochastic approximation (SPSA) method. A linear transformation is introduced to convert the free model into a linear model so that a conventional linear controller design method can be applied. In this paper, the feasibility of the proposed method is demonstrated in a one-machine infinite bus power system. The linear quadratic regulator (LQR) method is applied to the free model to design a PSS for the system, and compared with the conventional PSS. The proposed SPSA-based LQR controller is robust in different loading conditions and system failures such as the outage of a major transmission line or a three phase to ground fault which causes the change of the system structure

Intelligent Monitoring System with High Temperature Distributed Fiberoptic Sensor for Power Plant Combustion Processes

The objective of the proposed work is to develop an intelligent distributed fiber optical sensor system for real-time monitoring of high temperature in a boiler furnace in power plants. Of particular interest is the estimation of spatial and temporal distributions of high temperatures within a boiler furnace, which will be essential in assessing and controlling the mechanisms that form and remove pollutants at the source, such as NOx. The basic approach in developing the proposed sensor system is three fold: (1) development of high temperature distributed fiber optical sensor capable of measuring temperatures greater than 2000 C degree with spatial resolution of less than 1 cm; (2) development of distributed parameter system (DPS) models to map the three-dimensional (3D) temperature distribution for the furnace; and (3) development of an intelligent monitoring system for real-time monitoring of the 3D boiler temperature distribution. Under Task 1, we have set up a dedicated high power, ultrafast laser system for fabricating in-fiber gratings in harsh environment optical fibers, successfully fabricated gratings in single crystal sapphire fibers by the high power laser system, and developed highly sensitive long period gratings (lpg) by electric arc. Under Task 2, relevant mathematical modeling studies of NOx formation in practical combustors have been completed. Studies show that in boiler systems with no swirl, the distributed temperature sensor may provide information sufficient to predict trends of NOx at the boiler exit. Under Task 3, we have investigated a mathematical approach to extrapolation of the temperature distribution within a power plant boiler facility, using a combination of a modified neural network architecture and semigroup theory. Given a set of empirical data with no analytic expression, we first developed an analytic description and then extended that model along a single axis

Integrating Research Results into a Power Engineering Curriculum

This paper presents summaries of the activities of six research active power engineering educators which were presented in a panel session of the same name at the IEEE Power Engineering Society Winter Meeting on February 3, 1997 in New York City, USA. Each of the panelists discusses how research results are incorporated into courses and how students benefit from this approach

Magnolin targeting of ERK1/2 inhibits cell proliferation and colony growth by induction of cellular senescence in ovarian cancer cells

Ras/Raf/MEKs/ERKs and PI3 K/Akt/mTOR signaling pathways have key roles in cancer development and growth processes, as well as in cancer malignance and chemoresistance. In this study, we screened the therapeutic potential of magnolin using 15 human cancer cell lines and combined magnolin sensitivity with the CCLE mutaome analysis for relevant mutation information. The results showed that magnolin efficacy on cell proliferation inhibition were lower in TOV‐112D ovarian cancer cells than that in SKOV3 cells by G1 and G2/M cell cycle phase accumulation. Notably, magnolin suppressed colony growth of TOV‐112D cells in soft agar, whereas colony growth of SKOV3 cells in soft agar was not affected by magnolin treatment. Interestingly, phospho‐protein profiles in the MAPK and PI3 K signaling pathways indicated that SKOV3 cells showed marked increase of Akt phosphorylation at Thr308 and Ser473 and very weak ERK1/2 phosphorylation levels by EGF stimulation. The phospho‐protein profiles in TOV‐112D cells were the opposite of those of SKOV3 cells. Importantly, magnolin treatment suppressed phosphorylation of RSKs in TOV‐112D, but not in SKOV3 cells. Moreover, magnolin increased SA‐β‐galactosidase‐positive cells in a dose‐dependent manner in TOV‐112D cells, but not in SKOV3 cells. Notably, oral administration of Shin‐Yi fraction 1, which contained magnolin approximately 53%, suppressed TOV‐112D cell growth in athymic nude mice by induction of p16Ink4a and p27Kip1. Taken together, targeting of ERK1 and ERK2 is suitable for the treatment of ovarian cancer cells that do not harbor the constitutive active P13 K mutation and the loss‐of‐function mutations of the p16 and/or p53 tumor suppressor proteins