A Control Structure for Smooth Transfer From Grid-Connected to Islanded Operation of Distributed Synchronous Generators

2020 ◽  
Vol 35 (2) ◽  
pp. 929-936
Author(s):  
Artur B. Piardi ◽  
Edson L. Geraldi ◽  
Ahda P. Grilo ◽  
Romeu Reginatto ◽  
Rodrigo A. Ramos
2020 ◽  
Vol 216 ◽  
pp. 01023
Author(s):  
Pavel Ilyushin ◽  
Aleksandr Simonov

Inverter generator sets (GS) are increasingly common in the electricity industry. The paper dwells upon the core advantages and issues of integrating inverter generator sets that must be considered at the design stage to make informed decisions. The authors present examples of computing the electrical parameters of inverter generator sets in a variety of operating situations. The calculated electromechanical transients show inverter GS’s are more efficient compared to conventional synchronous generators for grid nodes that are ‘weakly connected’ to the grid as well as for islanded operation. The paper further proves that automatic control systems of GS inverters can feasibly feature parameter control laws that conform to the general and additional requirements of the system, which in turn are based on the parameter calculations. It shows that a feasibility study is needed to decide whether to use inverter GS’s.


Author(s):  
A. M. Oleynikov ◽  
L. N. Kanov

The paper gives the description of the original wind electrical installation with mechanical reduction in which the output of vertical axis wind turbine with rather low rotation speed over multiplicator is distributed to a certain number of generators. The number of acting generators is determined by the output of actual operating wind stream at each moment. According to this constructive scheme, it is possible to provide effective and with maximum efficiency installation work in a wide range of wind speeds and under any schedule issued to the consumer of electricity. As there are no any experience in using such complexes, mathematical description of its main elements is given, namely windwheels, generators with electromagnetic excitation of magnetic electrical type, then their interaction with windwheel, and also the results of mathematical modeling of work system regimes under using the offered system of equations. The basis for the mathematical description of the main elements of the installation – synchronous generators – are the system of equations of electrical and mechanical equilibrium in relative units in rotating coordinates without considering saturation of the magnetic circuit. The equation of mechanical equilibrium systems includes torque and brake windwheel electromagnetic moments of generators with taking into account the reduction coefficients and friction. In addition, we specify the alternator rotor dynamics resulting from continuous torque of windwheel fluctuations under the influence of unsteady wind flow and wind speed serving as the original variable is modeled by a set of sinusoids. Model simplification is achieved by equivalization of similar generators and by disregarding these transitions with a small time constant. Calculation the installation with synchronous generators of two types of small and medium capacity taking into account the operational factors allowed us to demonstrate the logic of interactions in the main elements of the reported complex in the process of converting wind flow into the generated active and reactive power. We have shown the possibility of stable system work under changeable wind stream condition by regulating of the plant blade angle and with simultaneous varying of generator number of different types. All these are in great interest for project organizations and power producers.


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