Dynamics Analysis of Two Synchronous Machines Interconnected with a Distribution Network in ATP-EMTP

Abstract

The main task in this paper is to present a performance analysis of a distribution network in the presence of two synchronous generators in parallel, with its speed and voltage regulators modeled with TACS - Transient Analysis of Control Systems, for distributed generation studies. This type of configuration is common in systems where renewable fuels are used as sugar cane bagasse or straw. Must be highlighted that this generators is driven by a steam turbine, and the whole system with regulators and the equivalent of the power authority system in the point of connection (PAC) are modeled in the ATP - Alternative Transients Program. Technical questions studied here refer to steady-state voltage profile, voltage stability, voltage dip due to a balanced three-phase fault, load rejection, distribution line outage and the behavior of machine regulators facing the aforementioned contingencies. Results show that, in some cases, the independent power producer (IP) can be a menace to the physical integrity of the system and in other cases can be very beneficial to the distribution system in the point of connection. Keywords—distributed generation, synchronous generator, voltage profile, voltage regulator, speed regulator. I. NOMENCLATURE t V - voltage at the independent generator bus bar (pu), ref V - reference voltage (pu), a K - regulator gain, e K - exciter constant related to self-excited field, f K - time gain for the regulator stabilizer circuit, a T - regulator amplified time constant (s), r T - regulator input filter time constant, e T - exciter time constant, f T - time constant for the regulator stabilizer circuit (s), max E - maximum exciter output voltage (applied to generator field), min E - minimum exciter output voltage (applied to generator field), () e Vf E = f - saturation function, max V - maximum limit for the regulator output voltage (pu), min V - minimum limit for the regulator output voltage (pu), f E - field voltage (pu), n S - rated aparent power, n U - rated voltage, L - lenght, A R - armature resistance (pu), L x - armature leakage reactance (pu), d x - direct axis reactance (pu), q x - quadrature axis reactance (pu), `d x - direct axis transient reactance (pu), `q x - quadrature axis transient reactance (pu), `` d x - direct axis sub transient reactance (pu), `` q x - quadrature axis sub transient reactance (pu), 0 x - zero sequence reactance (pu),