Stand-alone power system

About: Stand-alone power system is a research topic. Over the lifetime, 8650 publications have been published within this topic receiving 192397 citations. The topic is also known as: Stand-alone photovoltaic power system.

A Supervisory Power Management System for a Hybrid Microgrid With HESS

Abstract: This paper proposes a supervisory power management system (PMS) for a grid interactive microgrid with a hybrid energy storage system. The key feature of the proposed PMS is reduced number of sensors required to implement the PMS. The PMS considers renewable power variation, grid availability, electricity pricing, and changes in local loads. It can detect the operating mode of system without measuring load currents and powers. A single-phase voltage source converter (VSC) transfers real power between dc grid and utility grid besides offering ancillary services such as harmonic mitigation, reactive power support, and unity power factor at the point of common coupling (PCC). In the proposed system, a better dc-link voltage regulation is achieved and the usage of supercapacitors reduces the current stress on the battery. The PMS also addresses extreme operating conditions such as load shedding, off-maximum power point tracking operation of photovoltaic, elimination of critical oscillation of hybrid energy storage systems power, islanded operation, and resynchronization with grid. The performance of the proposed PMS is verified by digital simulation and experimental studies.

Potential of Heat Pumps for Demand Side Management and Wind Power Integration in the German Electricity Market

Abstract: Increasing power system flexibility by responsive demand is a central issue for the incorporation of higher levels of variable wind generation in future power systems. The electrification of the heat sector, except from energy efficiency gains, may offer a vast potential of new forms of flexible demand, by time-shifting of heat production in buildings. The assessment of this potential can, however, be performed only when the limitations imposed by the primary operation of the equipment (space heating) are realistically taken into account. In this paper, a methodology is presented for the quantification of the flexibility offered by the thermal storage of building stock equipped with heat pumps, to power systems with significant penetration of wind power. A model is proposed for the incorporation of the building stock thermal behavior as equivalent energy storage in electricity market models. At the same time, the model allows the coupling to a detailed dynamic thermal model of buildings for the assessment of the respective operational restrictions. The case study presents the results of a project for the evaluation of the flexibility offered by portfolios of high heat pump deployment in conjunction with high wind penetration scenarios for the future German electricity system.

Flexible Operation of Batteries in Power System Scheduling With Renewable Energy

Abstract: The fast growing expansion of renewable energy increases the complexities in balancing generation and demand in the power system. The energy-shifting and fast-ramping capability of energy storage has led to increasing interests in batteries to facilitate the integration of renewable resources. In this paper, we present a two-step framework to evaluate the potential value of energy storage in power systems with renewable generation. First, we formulate a stochastic unit commitment approach with wind power forecast uncertainty and energy storage. Second, the solution from the stochastic unit commitment is used to derive a flexible schedule for energy storage in economic dispatch where the look-ahead horizon is limited. Analysis is conducted on the IEEE 24-bus system to demonstrate the benefits of battery storage in systems with renewable resources and the effectiveness of the proposed battery operation strategy.

ILST Control Algorithm of Single-Stage Dual Purpose Grid Connected Solar PV System

Abstract: This paper presents a single-stage, three-phase grid connected solar photovoltaic (SPV) system. The proposed system is dual purpose, as it not only feeds extracted solar energy into the grid but it also helps in improving power quality in the distribution system. The presented system serves the purpose of maximum power point tracking (MPPT), feeding SPV energy to the grid, harmonics mitigation of loads connected at point of common coupling (PCC) and balancing the grid currents. The SPV system uses a three-phase voltage source converter (VSC) for performing all these functions. An improved linear sinusoidal tracer (ILST)-based control algorithm is proposed for control of VSC. In the proposed system, a variable dc link voltage is used for MPPT. An instantaneous compensation technique is used incorporating changes in PV power for fast dynamic response. The SPV system is first simulated in MATLAB along with Simulink and sim-power system toolboxes, and simulated results are verified experimentally. The proposed SPV system and its control algorithm are implemented in a three-phase distribution system for power quality improvement and improved utilization of VSC. The total harmonics distortions (THDs) of grid currents and PCC voltages are observed within IEEE-929 and IEEE-519 standards.

Real-Time Optimization for Power Management Systems of a Battery/Supercapacitor Hybrid Energy Storage System in Electric Vehicles

Abstract: Batteries mounted on electric vehicles (EVs) are often damaged by high peak power and rapid charging/discharging cycles, which are originated from repetitive acceleration/deceleration of vehicles particularly in urban situations. To reduce battery damage, the battery/supercapacitor (SC) hybrid energy storage system (HESS) has been considered as a solution because the SC can act as a buffer against large magnitudes and rapid fluctuations in power. While the traditional purpose of employing the HESS in EVs is to minimize the magnitude/variation of battery power or power loss, the previous approaches proposed for controlling the HESS have some drawbacks; they neither consider these objectives simultaneously nor reflect real-time load dynamics for computing the SC reference voltage. In this paper, we present a power control framework consisting of two stages: one for computing the SC reference voltage and another for optimizing the power flowing through the HESS. In the presented framework, we propose a methodology for calculating the SC reference voltage considering the real-time load dynamics without given future operation profiles. In addition, we formulate the HESS power control problem as a convex optimization problem that minimizes the magnitude/fluctuation of battery power and power loss at the same time. The optimization problem is formulated so that it can be repeatedly solved by general solvers in polynomial time. Simulation results carried out on MATLAB show that the magnitude/variation of battery power and power loss can be concurrently reduced in real time by the proposed framework.