Evaluation of Residential PV-EV System for Supply and Demand Balance of Power System

2015 ◽  
Vol 135 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Mustapha Aachiq ◽  
Joao Gari da Silva Fonseca Junior ◽  
Takashi Oozeki ◽  
Yumiko Iwafune
Keyword(s):  
Power System ◽  
Supply And Demand ◽  
Balance Of Power

Evaluation of Residential PV-EV System for Supply and Demand Balance of Power System

2016 ◽  
Vol 195 (2) ◽  
pp. 11-20 ◽  
Author(s):  
MUSTAPHA AACHIQ ◽  
JOAO GARI DA SILVA FONSECA JUNIOR ◽  
TAKASHI OOZEKI ◽  
YUMIKO IWAFUNE
Keyword(s):  
Power System ◽  
Supply And Demand ◽  
Balance Of Power

scholarly journals Dynamics Analysis Using Koopman Mode Decomposition of a Microgrid Including Virtual Synchronous Generator-Based Inverters

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4581
Author(s):  
Yuko Hirase ◽  
Yuki Ohara ◽  
Naoya Matsuura ◽  
Takeaki Yamazaki
Keyword(s):  
Power System ◽  
System Dynamics ◽  
Dimensional Space ◽  
Supply And Demand ◽  
Transient State ◽  
Synchronous Generator ◽  
Response Analysis ◽  
Power System Dynamics ◽  
Mode Decomposition ◽  
Virtual Synchronous Generator

In the field of microgrids (MGs), steady-state power imbalances and frequency/voltage fluctuations in the transient state have been gaining prominence owing to the advancing distributed energy resources (DERs) connected to MGs via grid-connected inverters. Because a stable, safe power supply and demand must be maintained, accurate analyses of power system dynamics are crucial. However, the natural frequency components present in the dynamics make analyses complex. The nonlinearity and confidentiality of grid-connected inverters also hinder controllability. The MG considered in this study consisted of a synchronous generator (the main power source) and multiple grid-connected inverters with storage batteries and virtual synchronous generator (VSG) control. Although smart inverter controls such as VSG contribute to system stabilization, they induce system nonlinearity. Therefore, Koopman mode decomposition (KMD) was utilized in this study for consideration as a future method of data-driven analysis of the measured frequencies and voltages, and a frequency response analysis of the power system dynamics was performed. The Koopman operator is a linear operator on an infinite dimensional space, whereas the original dynamics is a nonlinear map on a finite state space. In other words, the proposed method can precisely analyze all the dynamics of the power system, which involve the complex nonlinearities caused by VSGs.

State Formation in Korea and Japan, 400–800 CE: Emulation and Learning, Not Bellicist Competition

2021 ◽  
pp. 1-31
Author(s):  
Chin-Hao Huang ◽  
David C. Kang
Keyword(s):  
Power System ◽  
Public Goods ◽  
East Asia ◽  
State Formation ◽  
Balance Of Power ◽  
Internal Stability ◽  
State Institutions ◽  
Bureaucratic Control ◽  
Administrative Capacity ◽  
Competition State

Abstract State formation occurred in Korea and Japan 1,000 years before it did in Europe, and it occurred for reasons of emulation and learning, not bellicist competition. State formation in historical East Asia occurred under a hegemonic system in which war was relatively rare, not under a balance-of-power system with regular existential threats. Korea and Japan emerged as states between the fifth and ninth centuries CE and existed for centuries thereafter with centralized bureaucratic control defined over territory and administrative capacity to tax their populations, field large militaries, and provide extensive public goods. They created these institutions not to wage war or suppress revolt: the longevity of dynasties in these countries is evidence of both the peacefulness of their region and their internal stability. Rather, Korea and Japan developed state institutions through emulation and learning from China. The elites of both copied Chinese civilization for reasons of prestige and domestic legitimacy in the competition between the court and the nobility.

The Balance of Power in World Politics

2016 ◽  
Author(s):  
Randall L. Schweller
Keyword(s):  
Power System ◽  
Balance Of Power ◽  
World Politics ◽  
Shared Responsibility ◽  
Normal Operation ◽  
Democratic Peace ◽  
Material Forces ◽  
Power Politics ◽  
Core Theory ◽  
Minimum Requirements

The balance of power—a notoriously slippery, murky, and protean term, endlessly debated and variously defined—is the core theory of international politics within the realist perspective. A “balance of power” system is one in which the power held and exercised by states within the system is checked and balanced by the power of others. Thus, as a nation’s power grows to the point that it menaces other powerful states, a counter-balancing coalition emerges to restrain the rising power, such that any bid for world hegemony will be self-defeating. The minimum requirements for a balance of power system include the existence of at least two or more actors of roughly equal strength, states seeking to survive and preserve their autonomy, alliance flexibility, and the ability to resort to war if need be. At its essence, balance of power is a type of international order. Theorists disagree, however, about the normal operation of the balance of power. Structural realists describe an “automatic version” of the theory, whereby system balance is a spontaneously generated, self-regulating, and entirely unintended outcome of states pursuing their narrow self-interests. Earlier versions of balance of power were more consistent with a “semi-automatic” version of the theory, which requires a “balancer” state throwing its weight on one side of the scale or the other, depending on which is lighter, to regulate the system. The British School’s discussion of balance of power depicts a “manually operated” system, wherein the process of equilibrium is a function of human contrivance, with emphasis on the skill of diplomats and statesmen, a sense of community of nations, of shared responsibility, and a desire and need to preserve the balance of power system. As one would expect of a theory that made its appearance in the mid-16th century, balance of power is not without its critics. Liberals claim that globalization, democratic peace, and international institutions have fundamentally transformed international relations, moving it out of the realm of power politics. Constructivists claim that balance of power theory’s focus on material forces misses the central role played by ideational factors such as norms and identities in the construction of threats and alliances. Realists, themselves, wonder why no global balance of power has materialized since the end of the Cold War.

scholarly journals A Study on Optimal Power System Reinforcement Measures Following Renewable Energy Expansion

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5929
Author(s):  
Hyuk-Il Kwon ◽  
Yun-Sung Cho ◽  
Sang-Min Choi
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Large Scale ◽  
Supply And Demand ◽  
Electricity Supply ◽  
Static And Dynamic Analysis ◽  
The Future ◽  
Reinforcement Measures

Renewable energy generation capacity in Korea is expected to reach about 63.8 GW by 2030 based on calculations using values from a power plan survey (Korea’s renewable energy power generation project plan implemented in September 2017) and the “3020” implementation plan prescribed in the 8th Basic Plan for Long-Term Electricity Supply and Demand that was announced in 2017. In order for the electrical grid to accommodate this capacity, an appropriate power system reinforcement plan is critical. In this paper, a variety of scenarios are constructed involving renewable energy capacity, interconnection measures and reinforcement measures. Based on these scenarios, the impacts of large-scale renewable energy connections on the future power systems are analyzed and a reinforcement plan is proposed based on the system assessment results. First, the scenarios are categorized according to their renewable energy interconnection capacity and electricity supply and demand, from which a database is established. A dynamic model based on inverter-based resources is applied to the scenarios here. The transmission lines, high-voltage direct current and flexible alternating current transmission systems are reinforced to increase the stability and capabilities of the power systems considered here. Reinforcement measures are derived for each stage of renewable penetration based on static and dynamic analysis processes. As a result, when large-scale renewable energy has penetrated some areas in the future in Korean power systems, the most stable systems could be optimally configured by applying interconnection measure two and reinforcement measure two as described here. To verify the performance of the proposed methodology, in this paper, comprehensive tests are performed based on predicted large-scale power systems in 2026 and 2031. Database creation and simulation are performed semi-automatically here using Power System Simulator for Engineering (PSS/E) and Python.

scholarly journals Flexibility Evaluation Method of Power Systems with High Proportion Renewable Energy Based on Typical Operation Scenarios

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 627
Author(s):  
Xiangying Tang ◽  
Yan Hu ◽  
Zhanpeng Chen ◽  
Guangzeng You
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Supply And Demand ◽  
Flow Distribution ◽  
Occurrence Probability ◽  
Flexible Operation

The development of renewable energy represented by wind, photovoltaic and hydropower has increased the uncertainty of power systems. In order to ensure the flexible operation of power systems with a high proportion of renewable energy, it is necessary to establish a multi-scenario power system flexibility evaluation method. First, this study uses a modified k-means algorithm to cluster operating scenarios of renewable energy and load to obtain several typical scenarios. Then, flexibility evaluation indices are proposed from three perspectives, including supply and demand balance of the zone, power flow distribution of the zone and transmission capacity between zones. Next, to calculate the flexibility evaluation indices of each scenario—and according to the occurrence probability of each scenario—we multiplied the indices of each scenario by the scenario occurrence probability to obtain comprehensive evaluation indices of all scenarios. Based on the actual historical output data of renewable energy and load of a southern power system in China, a flexibility evaluation was performed on the modified IEEE 14 system and modified IEEE 39 system. The results show that the proposed clustering method and flexibility indices can effectively reflect the flexibility status of the power system.

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