Damping of inter-area oscillations by combining control strategies in hydropower plants

This paper examines how the damping capability can be improved if inter-area oscillations occur by combining control strategies in hydropower plants. First, the control challenges of hydropower plants, such as the water hammer effect, are discussed. In a single-machine infinite bus system (SMIBS), the use of a Power System Stabilizer (PSS) in the generator excitation and in the governor control path as well as the combination of both strategies are examined for their effectiveness in terms of their damping capability. In addition, these results are compared with an optimal state space controller with an observer as a damping element. The Heffron-Phillips model is the design model for the PSS as well as for the model-based controller. The verification of the damping capability through the PSS variants is evaluated by using a three-machine model in the time domain and by using modal analysis.

Implementasi Kontrol Fuzzy Logic pada Kontrol Takar Cairan Otomatis

Berkembangnya teknologi yang dibangun dalambidang teknologi industri. Salah satu yang utama ialahuntuk menakar cairan yang mendekati presisi, danmenghindari fenomena water hammer effect yang menjadimasalah pada proses flow cairan, ini terjadi ketika valveyang digunakan untuk menutup saluran ditutup denganrentang waktu singkat dan berdampak pada sistem takarcairan tidak dapat bekerja dengan penakaran yangmendekati akurat. Hal ini menyenbabkan berkurangnyakualitas pada sistem penakar cairan. Solusi yang ditawarkanyaitu berupa proses pada sistem kendali dengan mengurangikemungkinan terjadi water hammer effect dan errorpenakaran cairan dengan mengaplikasikan Kontrol LogikaFuzzy (KLF) pada sistem. Dengan mengimplementasiakankendali cerdas, servo Valve dapat diatur agar aktif tidakhanya pada posisi menutup “0” atau membuka “1” saja,penggunaan valve secara otomatis dengan kontroler dapatmengurangi tenaga konvensional, proses produksi lebihpresisi karena bersifat computerize. Karena membutuhkankepresisian saat penakaran maka dibangunlah sistemkendali takar cairan otomatis yang dikendalikan agarpekerjaan menjadi lebih mudah dan efisien denganmenggunakan diaphragm pump motor DCyang dapatdikendalikan menggunakan driver PWM, agar takar cairanmendekati akurat digunakan motor servo MG996 untukmengontrol valvediharapkan agar tidak menutup valvesecara manual oleh user. Sistemscanning water flow secarabertahap terbaca oleh flow sensor OF05ZAT dapatditentukan dengan keakurasian yang relatif tinggi.Diharapkan dengan adanya takar cairan tersebut dapatmeningkatkan efektivitas produksi demi menciptakansistem penakar cairan yang mendekati akurat.

Process of pasta products forming in matrix wells with pre-compaction, plasticization and heating of dough

The existing designs of domestic and foreign matrices lack pre-compaction, plasticization and heating of dough, which leads to significant hydraulic resistance in the area where dough flow enters the forming holes of the dies and increases energy consumption, while in typical matrices the cross section of deep and empty wells is much larger than the total area of forming holes. The dough flow almost becomes uncontrollable, and this leads to water hammer effect and destruction of dies. This problem can be solved by installing special inserts in in the matrix wells (depth of wells is 50-120 mm). The paper shows a new direction in design of matrices for production of pasta, in particular, it is proposed to install spiral inserts in the wells of matrix, manufactured in the form of Venturi tubes. Rheological basis of dough flow in the cylindrical channels of the insert are considered, mathematical models for determination of the dough volume flow rate and dough flow rate are constructed. It is theoretically established that the volume flow rate of the dough Q0 and its flow rate depend on the length of the cylindrical channel and the viscosity of dough. The results of experimental researches are presented. It is empirically established that the inserts located in the wells of the matrix pre-compact dough, plasticize and heat it, the productivity of the press machine MIT-2 due to increasing the speed of extrusion is increased averagely by 25-26 % with significant improvement in quality of the formed semi-finished products and reduction of energy consumption.