Out of the total generation of power, a large part of it is being met by the conventional power sources like thermal, hydro, and nuclear. However, due to some inherent disadvantages like increased environmental impact, decreased water availability and radiation hazards of the conventional power sources more emphasis is being given to tap the non-conventional resources like solar, tidal, geothermal and wind energy in the present time. However, the utilization of these resources which are usually dispersed in nature make the operation of the power system very complex. Therefore, studies like optimal power flow, unit commitment, steady state stability and transientstability of such a complex system need to be addressed and studied. The transientstability being very crucial for the operation of the system has to be studied for a wind interconnected power system. Transientstability entails the evaluation of a power system’s ability to withstand large disturbances and to survive the transition to another operating condition. These disturbances may be faults such as a short circuit on a transmission line, loss of a generator, loss of a load, gain of load or loss of a portion of transmission network .
brought back to synchronism. While this can be done readily with gas and water turbine generators, steam turbine generators require many hours to rebuild steam and the operator has to shed load to compensate for the loss of generators. Loss of synchronism may also cause some protective relays to operate falsely and trip the circuit breakers of unfaulted lines. In such cases the problem becomes very complicated and may result in more generators losing synchronism. Therefore, transientstability of power systems becomes a major factor in planning and day-to-day operations and there is a need for fast on-line solution of transientstability to predict any possible loss of synchronism and to take the necessary measures to restore stability. Since then several studies have been conducted and new concepts and directions have been suggested to prevent instability and ensure security and reliability of power systems such as direct method Lyapunov's and pattern recognition which have been introduced for fast assessment of transientstability and eventually to implement these methods for on-line applications. Catastrophe theory has been pragmatic to the study of stability of various dynamic systems  and in recent years to the steady state stability problem of power systems by Sallam and Dineley . An attractive feature of Catastrophe Theory is that the stability regions are defined in terms of the system parameters bounded by the lines of stability limits. Tavora and Smith  introduced Centre Of Inertia (COI) technique for multi-machines power system which has been proven to give a good result in direct stability analysis. In this manuscript swallowtail catastrophe theory has been applied to find the sudden change of generator rotor angle operation. This is recognized as operational discontinuity in concept of Catastrophe Theory. It simplifies the transientstability assessment (TSA) problem by unifying diverse stability boundaries into the operational discontinuity.
Penelitian ini bertujuan untuk mempelajari dan menganalisis pengaruh perubahan reaktansi saluran terhadap transientstability dengan menerapkan gangguan lepasnya beban dan gangguan 3 fasa simetris yang terjadi pada salah satu saluran. Hasil simulasi menunjukkan kompensasi seri saluran dan penambahan jumlah saluran transmisi mampu menurunkan reaktansi saluran sehingga meningkatkan stabilitas sistem tenaga listrik. Selanjutnya, diperoleh Critical Clearing Time (CCT) dengan gangguan 3 fasa simetris adalah 0.19-0.20s. Dengan kompensasi 30%, 50% dan 70% diperoleh CCT berturut-turut 0.20-0.21s, 0.21-0.22s dan 0.22- 0.23s. Ketika penambahan jumlah saluran, diperoleh CCT sebesar 0.21-0.22s. Sedangkan lokasi gangguan hilangnya beban memberikan ayunan sudut rotor generator terdekat menjadi lebih besar dibandingkan dengan generator yang berada jauh dari lokasi terjadinya lepas beban.
In the electric power system, transientstability has a very important role in maintaining the safety and continuity of operations. In the event of interruption, the safety relay will work to open circuit breakers within a certain time. However, this does not guarantee the system stability can be maintained. This is due to the breaker time critical / critical clearing time (CCT) on the power system. CCT is the calculation of the critical time limit after which the interruption occurs during disturbances must be disconnected before the CCT. If the disorder is disconnected after CCT then the system can not be maintained its stability. With methods Time Domain Simulation (TDS) CCT values obtained are accurate but only in the form of limit values and limit unstable stable power system. At the PT. Fertilizer Sriwidjaja now has a time setting that is not considered a safety relay TransientStability Assessment. So that the company is more reliable and can maintain the continuity of production needs to be obtained CCT value TDS method. Having obtained the results of CCT is then used for the consideration of setting a safety relay. Results of the analysis showed that there are several buses in PT. Fertilizer Sriwidjaja the time setting is still above the value of the CCT. The addition of protective equipment that is able to work quickly is necessary, in this case the differential relay which is able to work 1-3 cycle disorders in order to isolate the system can be maintained its stability.
In the classical (vertical) power systems the synchronous operation of every interconnected synchronous machine (with its inherently rotating masses – inertia) is the main requirement for stable operation. As many of the distributed generation technologies are connected to the distribution network via power electronic interfaces, and do not contain inertia, the power system may show different transientstability phenomena. In this paper, the transientstability of power systems with (inertia less) converter connected distributed generation is explored via the Equal Area Criterion method and compared with that of a traditional (vertical) power system. With the existence of a strong external system, it is found that a system with a higher level of penetration of DG exhibits better stability, as measured by improved critical clearing times of the remaining synchronous generator(s).
PT Indonesia Chemical Alumina ("PT ICA") mengumumkan penunjukan konsorsium WIKA Group sebagai kandidat pertama kontraktor Engineering, Procurement and Construction (EPC) proyek Chemical Grade Alumina (CGA) Tayan. PT ICA merupakan perusahaan patungan antara ANTAM (IDX-ANTM; ASX-ATM), Showa Denko K.K. dan Marubeni Corporation dari Jepang. Sebagai perusahaan yang memproduksi 300.000 ton CGA per tahun. yang akan mengalami pengembangan sistem, tentu memerlukan analisa stabilitas transient supaya dapat menjaga kelangsungan plant yang akan dikembangkan sehingga dapat terus beroperasi tanpa terkendala gangguan pada sistem kelistrikan, agar selalu stabil pada saat produksi sebab apabila proses produksi terganggu oleh suplai listrik yang tidak setabil. Tugas akhir ini menganalisa kestabilan transien dan mekanisme pelepasan beban yang terdapat pada PT Indonesia Chemical Alumina ("PT ICA") sehingga dapat diperoleh keandalan dan kontinuitas yang layak. Pada tugas akhir ini analisis yang dilakukan meliputi kestabilan transien dan mekanisme pelepasan beban akibat generator outage(off), Short Circuit dan Motor Starting. Hasil simulasi menujukan bahwa lepasnya 1 generator ketika 1 generator ON memerlukan Load Shedding. Dalam kasus hubung singkat di salah satu bus, tegangan sistem turun hingga mencapai kondisi terendah sehingga diperlukan pengisolasian gangguan melalui pembukaan CB pada sumber gangguan selain itu kasus motor starting masih diperbolehkan pada saat 2 Generator ON
With the construction of UHVDC project, many areas have formed AC-DC hybrid transmission structure [1-2]. Regional interconnection of power grid can enhance economic operation, but it is easy to form weak links between groups of tightly coupled generations. On the other hand, quick response excitation system has been widely used in order to improve the transientstability of power grid. These factors will lead to insufficient damping of the interconnected system and increase the risk of regional power oscillation [3-4]. At the same time, Access of DC transmission put forward higher requirements in voltage supporting ability to the AC system. When there is an AC system fault, if not cleared immediately, it will make the DC converter voltage constantly low and cause a long time of commutation failure, which may cause DC block, thus affecting the stability of the interconnected system . According to the plan, China H province gradually form AC-DC hybrid power grid. Through the simulation, voltage stability and low-frequency oscillations will be the severe problems that impact security operation of receiver grid in the AC-DC hybrid system.
Kesimpulan: Tingkat kelincahan awal (pre test) pada kedua kelompok sebagian besar adalah poor, tingkat kelincahan setelah intervensi (post test) pada kelompok perlakuan sebagian besar adalah excellent, sedangkan pada kelompok kontrol sebagian besar adalah poor, dan hasil uji Wilcoxon Signed Rank Test dan uji Mann Whitney Test diperoleh kesimpulan terdapat pengaruh pemberian Core Stability Exercise terhadap peningkatan kelincahan pemain futsal.
Penelitian tentang pengaruh Core Stability Exercise dengan pendekatan Bobath Concept terhadap keseimbangan pasien pasca stroke yang dilakukan di Poli Spesialis Rehab Medik RSU Anwar Medika mulai tanggal 7 – 24 Maret 2017 dengan jumlah subyek penelitian sebanyak 2 pasien pasca stroke, dan mendapatkan perlakuan sebanyak 2 kali dalam seminggu selama 3 minggu diperoleh kesimpulan bahwa Core Stability Exercise dengan pendekatan Bobath Concept memberikan pengaruh terhadap peningkatan keseimbangan berdasarkan pengamatan dari penelitian dengan nilai hasil parameter dengan Berg Balance Scale . Peningkatan keseimbangan dapat di lihat berdasarkan hasil penelitian Berg Balance Scale bahwa adanya peningkatan nilai dari 14 item tes yang telah terlaksana.
V. Radu  and L. Cˇ adariu and V. Radu  have used this alternative fixed point theorem to study the stability for the Cauchy functional equation and the Jensen functional equation; and they present proofs for their Hyers-Ulam-Rassias stability. By their work, they unified the results of Hyers, Rassias and Gajda . We point out that the stability of these equations have been studied by S.-M. Jung , W. Jian  and other authors.
volume and activity of radioactive nuclear waste. In the R&D of FBR cycle system, development of long-life fuel cladding tube is a critical issue for enhancing the reactor performance (safety and economical performance), and the transmutation efficiency of minor actinide. Japan Atomic Energy Agency (JAEA) has been developing oxide dispersion strengthened (ODS) steels as a primary candidate of the long-life fuel cladding tube. The FBR fuel cladding tube will be exposed to the high-temperature up to 700 °C and high-dose neutron irradiation up to 250 dpa in normal operation condition. In the off-normal events, the cladding temperature up to 830 °C is permitted. Thus, evaluating the irradiation response of ODS steel at high-temperature is very important. The authors had carried out the neutron irradiation test of ODS ferritic steel cladding tube to neutron dose of 50 dpa at irradiation temperature of 400- 830 °C using JOYO 1) and BOR-60 2) . Since it takes long time to derive the high dose neutron irradiation data, the simulation irradiation technique using ion-accelerator is effective to evaluate the radiation tolerance of nuclear materials. This study uses the heavy ion beam, Fe-ion beam, for producing cascade damage. The irradiation test results using ion-beam and neutron of ODS ferritic steel reported so far are summarized in Table 1. Though irradiation data are not plentiful, the ODS ferritic steels developed by JAEA, JAEA-ODS, have been reported to have good microstructure stability. However, there are some reports indicating the irradiation-induced instability of dispersed oxide particles in the steels other than JAEA-ODS. This study carries out the simulation irradiation using Fe-ion beam to evaluate the high-dose irradiation response of JAEA-ODS, especially stability of nano-sized oxide particle, in FBR high burn-up core condition.
Latar Belakang: Jatuh sering dijumpai pada lansia dan resiko jatuh meningkat dengan pertambahan umur lansia. Dengan pertambahan usia terjadi penurunan keseimbangan dan perubahan postural tubuh, sehingga lansia rentan resiko jatuh. Lasia mempunyai banyak resiko bila mengalami jatuh antara lain patah tulang karena tingkat osteoporosis lansia cukup tinggi. Gangguan keseimbangan penyebab utama resiko jatuh lansia yang berakibat karena gannguan visual, vestibular dan somatosensoris. Tujuan: Penelitian ini bertujuan untuk Mengetahui Pengaruh penambahan latihan keseimbangan pada latihan core stability lebih baik terhadap resiko jatuh terhadap pada lansia. Metode penelitian: Penelitian ini menggunakan quasi eksprimental dengan pre and posttest group design. Populasi dalam penelitian ini adalah anggota posyandu lansia Aji Yuswo Dusun Ngebel, Kecamatan Kasihan, Kabupaten Bantul, total responden sebanyak 34 orang, dengan rincian kelompok I 17 orang, diberikan latihan core stability selama 2 minggu dengan frekuensi 2 kali seminggu. Pada kelompok II 17 orang, diberikan penambahan latihan latihan keseimbangan pada latihan Core Stability selama 2 minggu, dengan frekuensi 2 kali seminggu. Pengukuran resiko jatuh dilakukan dengan skala Morse, hasil penelitian dianalisa dengan menggunakan uji Wilcoxon. Hasil: Hasil penelitian uji Wilcoxon pada kelompok I p=0,317 (p>0,005) dengan rerata 15,47 berarti tidak ada pengaruh latihan Core Stability Terhadap resiko jatuh pada lansia dan kelompok II p=0,034 (p<0,05) dengan rerata 19,53 yang berarti ada pengaruh penambahan latihan keseimbangan pada latihan Core stability lebih baik terhadap resiko jatuh. Kesimpulan: penambahan latihan keseimbangan pada latihan Core stability lebih baik terhadap resiko jatuh. Saran: Penambahan jumlah sampel dan waktu dalam penelitian dalam penelitian berikutnya. Kata Kunci: Core Stabiliy, latihan keseimbangan, resiko jatuh lansia.
water for 2 h (T2), and then soaking was continued for 24 h (T24). The swelling and water absorption (WA) were measured for each level. Another test of TS was conducted on a wet-dry cycle. For the wet-dry cyclic test, the specimens were subjected to dimensional stability evaluation under the following wet-dry conditioning cycles. During the first cycle of this process, boards were soaked in 20 °C water for 24 h (W1) and then they were oven-dried at 50 °C for 22 h (D1). During the second cycle, the boards were soaked in 70 °C water for 2 h (W2) and then oven-dried at 50 °C for 22 h (D2). During the third cycle, the boards were soaked in 100 o C water for 2 h (W3) and oven-dried at 50 °C for 22 h (D3). After these treatments, specimens of 50 mm by 50 mm were conditioned at 25 °C and 65% ± 5% RH until they reached equilibrium. The thickness changes of the boards were calculated based on initial measurements taken after the boards were dried at 60 °C for 22 h. Eight replicates for each condition were used.
Lightning strike to overhead electrical power cable or transmission line may cause the high effect of transient overvoltage which lead to permanent damages and affect the transmission line performance. These studies focus on the developing of lightning model as well as the cable model. PSCAD software is the main tools for the simulation works. Furthermore the effect of transient overvoltage to the cable with different parameters were observed by simulating and analyzing the proposed models. In addition, the pattern of the currents and voltages from different topologies and cable’s parameters were analyzed when the lightning current wave shape of 8/20 was performed. It is found that the patterns of phases currents such as the peak current, the unwanted frequency and the surge duration signal were similar to each other under different parameters of the cable. Similarly, it is observed that the pattern of the phases voltage such as the peak current, the unwanted frequency and the surge duration signal were similar to each other under different parameters of the cable. In addition, we investigated the direct strike to the transmission line model for the cable under hot temperature (38 Celcius) especially in tropical location such as in Malaysia. It appears that the peak current, the unwanted frequency and the surge duration was similar to the standard value provided by the factory. In future, this project may initiate for the study of scheme protection