Taiwan Power Research Articles

Evaluating the feasibility and economics of hydrogen storage in large-scale renewable deployment for decarbonization

Renewable energy (RE) is pivotal for achieving a net-zero future, with energy storage systems essential for maximizing its utility. This study introduces a modeling framework that simulates large-scale RE deployment in Taiwan, emphasizing hydrogen as a primary storage medium. Utilizing hourly time steps, the model assesses various energy generation and storage configurations to demonstrate the technical feasibility of meeting Taiwan's 2050 net-zero target, which calls for a 60 % RE share primarily through solar and wind resources. However, achieving this target and the ambitious goal of 100 % RE penetration requires substantial enhancements in both generation capacity and storage solutions. The research evaluates the economic impacts by analyzing the levelized cost of energy (LCOE), revealing that optimal configurations, such as a wind capacity of 30 GW with a 5 % minimum capacity factor constraint on electrolyzers, significantly reduce LCOE to $0.176/kWh, underscoring the cost-effectiveness of hydrogen storage compared to battery alternatives in large-scale settings. The study underscores the necessity for ongoing investigations into replacing thermal power plants and maintaining grid stability amidst high RE penetration. To fully harness Taiwan's RE potential and contribute to global sustainability, effective deployment of hydrogen storage will require robust stakeholder support, continual technological advancements, and enabling policies. This framework, while tailored to Taiwan's power system, offers insights applicable to various global contexts.

Enhanced-Online-Random-Forest Model for Static Voltage Stability Assessment Using Wide Area Measurements

Application of data mining based methods in online voltage stability assessment has attracted vast attentions in recent years. To account for significant system changes, most of the data mining based methods reconstruct an entire model based on the updated training database. Instead of entirely rebuilding a model in offline mode, this paper presents a novel online learning framework for monitoring the voltage stability of a transmission grid using wide area measurements. A new enhanced online random forest model based on the drift detection and online bagging techniques is proposed. It enables to online update the trees involving tree growth and/or tree replacement. The trees in the forest are then combined via a weighted majority voting, which makes the decision model better adapted to system changes. The framework was first demonstrated on the IEEE 57-bus system, and then applied to a practical power system, the Taiwan power (Taipower) system composed of 1821 buses. In addition to accuracy-based measures, robustness and speed of the proposed framework were also validated. Extensive studies demonstrate that the proposed framework is able to provide reliable and accurate online voltage stability assessment.

Dynamic modeling of the policy effect and development of electric power systems: A case in Taiwan

Electric power is the cornerstone of economic growth, as well as one of the major energy sources for modern society. Economic growth, the demand for electricity, the security of fuel supplies, power-generating technologies, and the impact on the environment must be considered in the development planning and policy making of electric power. In fact, the planning of electric power development and the establishment of power generation capacity are complex and dynamic processes, which are influenced by national policies, citizens’ acceptance, and domestic and international energy sources. Hence, this study adopted system dynamics methodology to explore the development of policy-based electric power planning in Taiwan, analyzed its system structure, and simulated the impact of energy source policies on Taiwan's power supply according to different scenarios of economic growth. The findings of this study showed that the power supply in Taiwan is mainly influenced by four sub-systems with three important level variables, including the installed capacity of thermal power, installed capacity of nuclear power, and installed capacity of renewable energy. Currently, Taiwan plans to eradicate nuclear power by 2025 and replace it with renewable energies, which could result in power shortages and power rationing.

GECM-Based Voltage Stability Assessment Using Wide-Area Synchrophasors

Voltage instability is a crucial issue in the secure operation of power grids. Several methods for voltage stability assessment were presented. Some of them are highly computationally intensive, while others are reported not to work properly under all circumstances. This paper proposes a new methodology based on the generator equivalent circuit model (GECM) and the phasor measurement unit (PMU) technology for online voltage stability monitoring of a power grid. First, the proposed methodology utilizes synchronized phasor (synchrophasor) measurements to determine the impedance parameters of a transmission grid by means of the recursive least squares (RLS) algorithm. Furthermore, it incorporates the dynamic models of generators to handle the cases with generator reactive power limit violations. After that, an enhanced voltage stability index with GECMs incorporated is developed for reliable and accurate voltage stability assessment. The proposed methodology was first demonstrated on several standard IEEE power systems, and then applied to a practical power system, the Taiwan power (Taipower) system. The test results demonstrate the flexibility and effectiveness of the proposed methodology.

Practical Considerations to Calibrate Generator Model Parameters Using Phasor Measurements

In recent years, techniques of using system disturbance data to validate generator models have been widely discussed. Dynamic model validation and calibration is becoming one of the important applications to smart grid initiative. As this kind of technique is utilized to validate generator model, procedures of data screening and reprocessing are essential because raw data obtained from measurement is not always satisfactory. Regarding model parameter calibration, system model is usually quite complicated with various parameters interacting with each other. Artificial intelligent tool is the prior option to save the laborious tuning process and enhance the parameter accuracy. This paper presents a guideline to validate and calibrate parameters of generating units using the record data from phasor measurement unit. Associated procedures for signal filtering on the measurement data, key parameters screening, intelligent search of model parameters, and cross check of legitimate parameters will be discussed in detail. Finally, two historical disturbance cases that happened in the Taiwan power (Taipower) system are applied in accordance with the proposed guideline to demonstrate its effectiveness on generator parameter validation and calibration.

Assessment of Potential Variability of Net Load Following the Integration of 3 GW Wind Power in Taiwan

The study concerns the ramp rate problem that is associated with the large-scale integration of wind power. As planned 3GW wind farms are built in Taiwan, the potential variability of the net load must be estimated to determine the flexibility requirement. This work will use numerical weather predictions in Taiwan to estimate total power output from 3 GW wind farms, and analyze the ramping characteristics of the net load using statistical approaches. Its results can provide the operators of Taiwan's power generation system an important reference for determining the required ramping capability in the future.

A Hybrid Diagnosis Approach on Transformer’s Insulating Oil

The immersed-oil power transformer is so vital equipment in power system that maintenance-engineers take more monitor from transformer’s insulating oil to diagnose what is condition of operation. Then the dissolved gas analysis (DGA) is known for an effective technique on detecting incipient faults in oil-immersed power transformers. In this paper, a practical method is presented which consists of the Roger & Dernenber Ratio Methods, the Linear SVM diagnosis, the Key Gas method and the Specification ANSI/IEEE C57.104 Standard. Thus, incipient faults in power immersed-oil transformers can be directly identified by a report’s form which is so easy understood that we can accurate of diagnosis transformer. The user only keys in the measured data of main gases such as H2, CH4, C2H2, C2H4, C2H6, and CO those gases were must decompose via ASTM-D3612. The diagnosis result was showed in texts. This paper was taken some data from Taiwan and Siemens Power Company to verify the program that was validation and accuracy of the transformer’s insulating oil diagnosis tool.

New self‐adaptive bat‐inspired algorithm for unit commitment problem

Bat-inspired algorithm (BA) is a new evolutionary meta-heuristics algorithm inspired by a known technique of bats for finding prey. This study presents a self-adaptive BA to solve the unit commitment (UC) problem. The applied self-adaptive technique increases the population diversity and improves the exploration power of BA which results in better solutions and higher speed of convergence in solving the UC problem. This study, also, applies simple methods to handle the minimum on-/off-time constraint and spinning reserve requirement in generation of all solutions directly and without using any penalty function. The performance of the proposed method is verified by applying 10 up to 100-unit systems as well as a Taiwan power (Taipower) 38-unit system in a 24 h scheduling horizon.

Reduction of acidification from electricity — Generating industries in Taiwan by Life Cycle Assessment and Monte Carlo optimization

Life Cycle Assessment (LCA) is a rather common tool for reducing environmental impacts while striving for cleaner processes. This method yields reliable information when input data is sufficient; however, in uncertain systems Monte Carlo (MC) simulation is used as a means to compensate for insufficient data. The MC optimization model was constructed from environmental emissions, process parameters and operation constraints. The results of MC optimization allow for the prediction of environmental performance and the opportunity for environmental improvement. The case study presented here focuses on the acidification improvement regarding uncertain emissions and on the available operation of Taiwan's power plants. The boundary definitions of LCA were established for generation, fuel refining and mining. The model was constructed according to objective functional minimization of acidification potential, base loading, fuel cost and generation mix constraints. Scenario simulations are given the different variation of fuel cost ratios for Taiwan. The simulation results indicate that fuel cost was the most important parameter influencing the acidification potential for seven types of fired power. Owing to the low operational loading, coal-fired power is the best alternative for improving acidification. The optimal scenario for acidification improvement occurred at 15% of the fuel cost. The impact decreased from 1.39 to 1.24 kg SO 2-eq./MWh. This reduction benefit was about 10.5% lower than the reference year. Regarding eco-efficiency at an optimum scenario level of 5%, the eco-efficiency value was − 12.4 $US/kg SO 2-eq. Considering the environmental and economical impacts, results indicated that the ratio of coal-fired steam turbine should be reduced.

Corrosion monitoring application in Taiwan's nuclear power plants

Corrosion monitoring methods have been applied extensively for system condition diagnosis, material degradation resistance evaluations, and water chemistry optimisation in Taiwan's boiling water and pressurised water reactor nuclear power plants. The online corrosion monitoring systems developed and currently applied in Taiwan are reviewed. Examples of applications discussed include electrochemical potential monitoring, online crack growth rate measurements, electrochemical noise monitoring, linear polarisation resistance monitoring, and potential drop pipe thinning monitoring. Online corrosion monitors have proven useful tools within the nuclear power plant monitoring systems currently installed and have achieved their specific objectives in the context of Taiwan's power plants.

A Hybrid Method for the Estimation of Power System Low-Frequency Oscillation Parameters

A hybrid method which combines four different algorithms for low-frequency oscillation parameter estimation using wide-area measurements is presented in this paper. The first algorithm is the discrete Fourier transform which is used to start the low-frequency oscillation estimation process. The second one is the finite-impulse response (FIR) window filter which is employed in filtering unwanted components, and window correction factor is provided to eliminate the side effect of FIR window filter. The third one is the prototype algorithm which is proposed to estimate low-frequency oscillation parameters, and the last one is the least-square error method which is employed to enhance the computational accuracy by varying the window size. This hybrid method has been implemented in wide-area phasor measurements system by Java language and is under test in Taiwan's power system. Matlab/Simulink simulation and field test results are provided in the present paper.

Integrating Direct Load Control With Interruptible Load Management to Provide Instantaneous Reserves for Ancillary Services

This paper presents a novel adaptive control strategy for integrating direct load control (DLC) with interruptible load management (ILM) to provide instantaneous reserves for ancillary services in deregulated power systems. Fuzzy dynamic programming is used to satisfy customers' requirements and yields a near optimal pre-scheduling of the DLC. Then, the energy payback associated with the DLC is further eliminated by the adaptive control strategy, which exploits interruptible loads to modify the DLC schedule in real-time. Through the developed adaptive control strategy, the influences of the load uncertainties and forecasting errors on the pre-scheduling of the DLC can also be excluded. The proposed algorithm was practically tested on the Taiwan power (Taipower) 38-unit system with 20 air-conditioner loads and 15 interruptible loads. The outcomes reveal that an exact amount of instantaneous reserves can be successfully acquired, and the results are robust against dynamic disturbances of the power system.

A Model Reference Adaptive Control Strategy for Interruptible Load Management

This paper presents a model reference adaptive control (MRAC) strategy for interruptible load management (ILM). The proposed MRAC strategy consists of fuzzy dynamic programming (FDP) and priority-based heuristics inference rule (PBHIR) to offer a flexible solution and a real-time adjusting scheme for the ILM problem. The customers' requirements can be dealt with by the fuzzy variables, and the optimal or near optimal schedule of interrupted load can be acquired through DP search scheme. Additionally, a PBHIR is further employed as a regulator for the MRAC to modulate the schedule of the interrupted load in real time. The influences of the load variations and forecasting errors on the outputs of the FDP can be eliminated by the MRAC. The proposed MRAC strategy is tested practically on the Dar-Gun substation in Taiwan power (Taipower) system. The test results demonstrate the feasibility and effectiveness of applying the proposed method to the ILM problem.

99/02256 MW SCR installation on new coal-fired utility project: Toan, D. P. and Uysal, T. A. Proc. Am. Power Conf., 1998, 60, (1), 541–545

NO{sub x} regulations in Germany and Japan in the mid-1980s resulted in the mandatory retrofit of Selective Catalytic Reduction (SCR) technology on many utility installations. The early 1990s brought SCR technology to small, single unit new coal fired installations around the world. This paper describes the application of high NO{sub x} reduction SCR technology to the first large scale, coal fired, multiple unit new installation. By integrating the SCR design into the initial boiler equipment arrangement and design, significant simplification of equipment arrangement resulted in project cost savings. The four 550 MW units at Taiwan Power`s Taichung 5--8 Power Plant were installed, commissioned (Unit 8 went on line in early 1997), and tested demonstrating the low NO{sub x} emission capabilities of SCR technology.

A systematic approach to evaluate the overall impact of the electric traction demands of a high-speed railroad on a power system

This paper introduces a systematic approach to the evaluation of the overall impact of the electric traction demands of a high-speed railroad (HSR) on a power system. These large unbalanced traction loads may cause system voltage and current unbalances and, therefore, overheat rotating machines, increase system losses, interfere with neighboring communication systems, and cause protection relays and measuring instruments to malfunction. Some of these problems may significantly affect the operation of the power system and other equipment connected to it. Hence, the proposed approach is oriented toward applications in system operation analysis rather than planning analysis. On the basis of the Newton-Raphson algorithm, a three-phase powerflow program was developed. In this program, most of the component models and solution techniques are those that were developed for three-phase power-flow studies. They are applied to accurately simulate a three-phase high-voltage network supplying the traction loads. Rigorous component models, such as generator, transmission line, power transformer and traction substation models, were incorporated into this program. By combining the electric demands of traction substations along an HSR, this program can be used to evaluate the overall impact of traction loads on a power system. On the basis of the simulation results, related improvement projects can be evaluated and conducted if necessary. This approach has been successfully tested on Taiwan's power system (Taipower system), to which the power-supply system of a planned HSR will be connected in the near future.

Fixed/switched type shunt capacitor planning of distribution systems by considering customer load patterns and simplified feeder model

A shunt capacitor planning strategy to reduce system resistive losses and improve voltage profile for distribution feeders has been proposed. The objective function consists of peak load loss, energy loss and shunt capacitor cost, while operational constraints such as bus voltage profile and real shunt capacitor size are considered throughout the overall solution procedure. A three-phase load flow program, which accounts for the mutual coupling effect between conductors, unbalanced loading among phases, and feeders with multiple lateral branches, is applied to enhance the computer simulation. The simplified feeder model has been developed to derive the equivalent circuit of minor lateral branches so that the data processing work for the feeder configuration can be reduced efficiently. Besides, the customer load patterns as well as the feeder load curve for various seasons are derived so that the section load behaviour can be estimated more realistically. According to the reactive load duration curve of the feeders studied, the capacitor operation strategy by considering both fixed and switched shunt capacitors is developed to determine the proper size, location and switching time of capacitors to enhance the system operation efficiency. Two practical feeders in the Taipower (Taiwan Power) distribution system are selected for demonstration to show the effectiveness of the proposed method. Capacitors with optimal size are installed according to the schemes derived by computer analysis. Field tests are then performed and the energy loss reduction as well as the improvement of power quality of the test feeders can be justified.

Evolutionary programming based economic dispatch for units with non-smooth fuel cost functions

This paper develops an efficient, general economic dispatch (ED) algorithm for generating units with nonsmooth fuel cost functions. Based on the evolutionary programming (EP) technique, the new algorithm is capable of determining the global or near global optimal dispatch solutions in the cases where the classical Lagrangian based algorithms cease to be applicable. Effectiveness of the new algorithm is demonstrated on two example power systems and compared to that of the dynamic programming, simulated annealing, and genetic algorithms. Practical application of the developed algorithm is additionally verified on the Taiwan power (Taipower) system. Numerical results show that the proposed EP based ED algorithm can provide accurate dispatch solutions within reasonable time for any type of fuel cost functions.

Automated Distribution System (DC Remote Control System)

This paper describes the principle and application of DC sequential transfer and the automated distribution system developed by the author. This system supervises and controls concentratedly section switches of primary feeders (6.6KV and 11KV) from a master station at the central office. The system enables reception and transmission of signals by means of control cables which connect between the master station and group of feeder terminal units which are combined with section switches. These switches are sequence circuits using electromagnetic relays and installed along the distribution power lines. This system was first put into service in 1976 and now a total of 26 systems have been under operation by the Chugoku Electric Power Co. and 2 systems by the Taiwan Power Co. They have been making considerable contribution to the management and operation of their distribution systems.