A strategy to enhance AGC performance of power systems that suffer inter-area oscillations and a case study for Turkish power system

Sufficient fast secondary reserve and its adequate dynamic activation are the key factors in satisfying automatic generation control (AGC) performance of a power system. Dynamic activation of the secondary reserves should also not introduce any negative damping to inter-area oscillations. This study presents a strategy to enhance AGC performance of a power system considering these concerns. Objective function is minimizing the amount of fast secondary reserves to mitigate ancillary service cost. The constraints are; AGC performance indices should be acceptable and AGC parameter settings should be adequate for inter-area oscillation concerns. In order to facilitate dynamic simulations, it is proposed to utilize a representative single bus common frequency dynamic model (SBCFDM) of the power system. The proposed strategy is based on optimizing the AGC parameters only for the time horizon when the loads are fluctuating most. Adequacy of the optimized AGC parameters are checked only for the worst loading scenario from inter-area oscillations concern point of view. It is showed that dynamic allocation of the secondary reserves twice a day is sufficient for satisfactory results. The proposed strategy is verified by its application to Turkish power system which suffers significant amount of fluctuating loads and inter-area oscillations with ENTSO/E grid

Abiraterone plus prednisone in metastatic, castration-sensitive prostate cancer

BACKGROUND: Abiraterone acetate, a drug that blocks endogenous androgen synthesis, plus prednisone is indicated for metastatic castration-resistant prostate cancer. We evaluated the clinical benefit of abiraterone acetate plus prednisone with androgen-deprivation therapy in patients with newly diagnosed, metastatic, castration-sensitive prostate cancer. METHODS: In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned 1199 patients to receive either androgen-deprivation therapy plus abiraterone acetate (1000 mg daily, given once daily as four 250-mg tablets) plus prednisone (5 mg daily) (the abiraterone group) or androgen-deprivation therapy plus dual placebos (the placebo group). The two primary end points were overall survival and radiographic progression-free survival. RESULTS: After a median follow-up of 30.4 months at a planned interim analysis (after 406 patients had died), the median overall survival was significantly longer in the abiraterone group than in the placebo group (not reached vs. 34.7 months) (hazard ratio for death, 0.62; 95% confidence interval [CI], 0.51 to 0.76; P<0.001). The median length of radiographic progression-free survival was 33.0 months in the abiraterone group and 14.8 months in the placebo group (hazard ratio for disease progression or death, 0.47; 95% CI, 0.39 to 0.55; P<0.001). Significantly better outcomes in all secondary end points were observed in the abiraterone group, including the time until pain progression, next subsequent therapy for prostate cancer, initiation of chemotherapy, and prostate-specific antigen progression (P<0.001 for all comparisons), along with next symptomatic skeletal events (P=0.009). These findings led to the unanimous recommendation by the independent data and safety monitoring committee that the trial be unblinded and crossover be allowed for patients in the placebo group to receive abiraterone. Rates of grade 3 hypertension and hypokalemia were higher in the abiraterone group. CONCLUSIONS: The addition of abiraterone acetate and prednisone to androgen-deprivation therapy significantly increased overall survival and radiographic progression-free survival in men with newly diagnosed, metastatic, castration-sensitive prostate cancer. (Funded by Janssen Research and Development; LATITUDE ClinicalTrials.gov number, NCT01715285 .)