Black Start Capability Research Articles

An integrated wind-photovoltaic-battery system with reduced power-electronic interface and fast control for grid-tied and off-grid applications

Abstract This paper proposes an integrated wind-photovoltaic-battery hybrid system that features a simple power management strategy, requires a lower number of power-electronic converters, and eliminates the need for dump loads. Thus, it is expected to offer a lower cost and higher efficiency, and to enable easier integration with distribution networks, as compared with a set of three stand-alone system. The power management strategy of the proposed hybrid system enables (1) rapid control of the wind and photovoltaic (PV) power outputs for tightly regulating the battery current, (2) off-grid operation with black-start capability, (3) grid-connected operation, and (4) safe transition from the grid-connected mode to the off-grid mode, and vice versa, without a need for communications with the host grid. Further, the proposed hybrid system is expected to have plug-and-play and power sharing capabilities and, therefore, suited for multi-generator remote electrification systems. The effectiveness of the proposed hybrid system is demonstrated through time-domain simulation studies in the PSCAD/EMTDC software environment.

A Sectionalizing Method in Power System Restoration Based on WAMS

This work presents a novel sectionalizing method for the build-up strategy in power system restoration. Power system restoration is the procedure of restoring power system elements after a partial or a complete blackout. Because of its economic and political importance, different strategies have been developed for a secure as well as fast restoration. One of the most practical and economical is the build-up strategy that includes the process of restoring separated parts (islands) in the power system and interconnecting them afterwards. This paper intends to develop a systematic algorithm for sectionalizing a power system considering various constraints such as black-start capability of generators, power supply-demand balance and independence of islands. Moreover, utilizing the Wide Area Measurement System (WAMS), each island will be fully observable in this method which is a crucial requirement for the restoration process. The New England 39 bus power system is used to demonstrate the proposed algorithm and verify the results. The proposed method is also applied to the IEEE 118 bus system as a large-scale power system to prove its capability in practical systems.

Restoration islands supplied by gas turbines

The paper describes how gas turbine based plants (open cycle and combined cycle) can be profitably used in power system restoration for supplying restoration areas. In recent times, in fact, several gas turbine sections entered the power system due to the improved efficiency of gas turbines and to the development of high efficiency combined-cycle plants. These units can be easily improved to provide black-start capability and can therefore largely increase the black-start capacity of the entire system. Restoration islands to be used for minimizing the time to supply critical areas, such as urban and industrial zones, can support the usual restoration paths designed to provide cranking power to large steam units. The paper presents the defining criteria for the procedures to be followed during restoration. An example referred to as an urban area is reported with simulation results. The Italian System Operator recently carried out some tests on an open cycle gas turbine aimed at checking the island operation of the unit. Some results are described.

Simulation of the Load Following Capability of a Repowered Plant During the First Phase of the System Restoration

The Italian restoration plan after a black out relics traditionally on the black-start capabilities of hydro power stations to start-up thermal units, During the last ten years, some of the Italian thermal plants have been repowered with combined cycles by topping the existing steam sections with gas turbines. Aim of this paper is to investigate whether and how the black-start capability of power plants gas sections could be used to start up the steam sections. This would improve the speed and reliability of the early restoration procedure. For such a purpose, a numerical simulator has been built using the Lego modular code, which allows getting a deeper insight about all problems concerning the black start-up procedure. The paper presents the results obtained by means of the simulator, which includes an additional control system (load scheduler), designed to operate simultaneously both the gas and steam sections as a single plant, during the initial phases of the restoration process. This additional control system can be useful to assist the plant operators, by avoiding untimely trip of generators, as well as by limiting the stress of the components and by speeding the restoration process.

New blackstart standards needed for competitive markets

Restructuring the electric-power industry may present new challenges for bulk-power reliability. The incentives to maintain and properly deploy system blackstart services that worked for vertically integrated utilities may not work when the system operator, the transmission system, and individual generators are in separate commercial organizations. The four North American power system interconnections are designed to be in continuous synchronized operation. Individual pieces of equipment are taken out of service for maintenance, but each interconnection as a whole is designed to run without interruption. Nevertheless, the power system must be prepared for the rare occasions when all or a major portion of the system is forced out of service. The author reviews the existing standards for blackstart capability, standards for the restructured industry, and system blackstart under restructuring.

Design features of the Murray Hydroelectric Project

The Murray Hydroelectric Project, a two-unit, 39 MW total rated capacity, run-of-the-river facility located on the Arkansas River, is described. The emphasis of the paper is on the project's electrical features. The two generating units are of an open-pit design with horizontal double-regulated turbines. Turbine rated speed in 46 RPM. The generator is rated 22.77 MW at a power factor of 0.9. The rated voltage is 6.9 kV. The author also discusses the plant's mechanical-hydraulic governor, its electrical system, a 5.7 mile (9.2l-km), 115 kV transmission line, the plant's black-start capability, its mechanical systems, and the plant, unit, and offsite control systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Design Features of the Murray Hydroelectric Project

The Murray Hydroelectric Project, a two-unit, 39 MW total rated capacity, run-of-the-river facility located on the Arkansas River, is described. The emphasis of the paper is on the project's electrical features. The two generating units are of an open-pit design with horizontal double-regulated turbines. Turbine rated speed in 46 RPM. The generator is rated 22.77 MW at a power factor of 0.9. The rated voltage is 6.9 kV. The author also discusses the plant's mechanical-hydraulic governor, its electrical system, a 5.7 mile (9.2l-km), 115 kV transmission line, the plant's black-start capability, its mechanical systems, and the plant, unit, and offsite control systems. >