No abstract

Active distribution network with energy storage system is an important outlet for a mass of distributed renewable energy connected to the grid. In this context, a hybrid energy storage system is proposed based on NaS battery and lithium ion battery, that the former is the main large scale energy storage technology world-widely used and developed and the latter is a flexible way to have both power and energy capacities. The hybrid energy storage system, which takes advantage of the two complementary technologies to provide large power and energy capacities, is chosen to do an evaluation of economical-environmental based on critical excess electricity production (CEEP), CO2 emission, annual total costs calculated on the specific given condition using Energy PLAN software. The result shows that hybrid storage system has strengths in environmental benefits and also can absorb more discarded wind power than single storage system and is a potential way to push forward the application of wind power and even other types of renewable energy resources.

The active distribution network is an effective approach to solve the problem such as the high penetration of intermittent renewable energy. This paper constructs single and hybrid energy storage battery systems in the active distribution network, calculates the economic benefits of the single and hybrid energy storage systems from six aspects in annual electricity sale revenue, ancillary revenue, investment cost, maintenance cost, landed cost and power shortage punishment cost. Take the lithium iron phosphate battery as single system, the lithium iron phosphate battery and Lithium titanate battery as the hybrid system to compute the cost benefit. The results show that the storage systems have effects to the intermittent renewable energy in peak shaving. Since the hybrid energy storage system can obtain more annual ancillary revenue, and the batteries’ work life is longer, it has more advantage in economic benefits than the single energy storage system.

Organic materials (cable particularly) aging has an adverse effect on the safety of productionsituations, and it is unscientific to replace organic materials blindly. A live evaluation system of organicmaterials aging was developed in present paper. This system consists of control and detection circuit(composed by ARM chip S3C6410 and force sensor, etc.) and servo drive motor. Compressivemodulus of organic materials was tested by the system with the help of mechanical system, so as toevaluate the cable aging.

With the enlargement of power grid scale, connections between different power subsystems in interconnected network have been more-closely related and the analysis of power system dynamic behaviors becomes more complex. This paper selects 3 area indexes which comprehensively reflect frequency change through transient process based on transient frequency stability curve and frequency change ratio curve, and there out builds the quantitative assessment method of frequency fluctuation characteristics. Then a generator set speed governor magnification-targeted optimization model, which determines the optimum of frequency fluctuation characteristics as optimal objective with proposed indexes, is built and solved by multivariate optimization algorithm. At last, an optimal example of practical power grid verifies the feasibility and validity of the proposed assessment method and the optimization model.