A Reactive Power Capacity Market Using Annual Auctions

Chapter 8 - Reactive power balance control based on flexibility theory

The robust curve-fitting based method for coordinated voltage regulation with distributed generator and OLTC in distribution network

In power grid reactive power and reactive power load, on the basis of well on the balance of the reactive power, reactive power compensation plan formulation, achieve reactive power onsite compensation at all levels of power grids, install capacitors with different reactive power capacity and locations. The effects of loss reduction and energy saving are also different. The optimal distribution of reactive power compensation capacity and location is actually a problem of planning optimization, which can be solved by non-linear programming methods. Aiming at the problem that it takes a long time to wait for maintenance and adjustment of tap position in the area of low voltage power consumption, this paper uses the nonlinear programming method to solve the optimal distribution of reactive power compensation capacity and position, so that the compensation capacitor with a certain capacity can achieve the maximum loss reduction effect.

To meet the requirements of real-time reactive power dispatch in wind farms, the method based on equal ratio of reactive power capacity is widely used, because it does not need power flow modeling and iterative solution. However, this method may cause the wind turbines (WT) with a long electrical distance to allocate too much reactive power, resulting in the terminal voltage exceeding the limit. Therefore, this paper proposes a reactive power allocation method based on dynamic weight adjustment of inverter capacity and electrical distance. First, the impact of WT power output on the voltage of each node in the system at different electrical distances was analyzed. Then, establish a reactive power dispatch model that takes the remaining capacity of the converter and electrical distance factors into account, and the weight coefficient between the two is dynamically adjusted based on voltage deviation by combining the idea of disturbance observation, achieve rapid distribution of reactive power commands without relying on detailed power flow modeling of the system. Finally, a 5 MW*25 wind farm case is used to verify the proposed method. The results show that the proposed method can effectively reduce the voltage deviation by more than 30% under the same reactive power scheduling instruction, and can improve the reactive power utilization of the wind farm.

With the development of science and technology, there has been growing the grid size, the growing demand for electricity and the extent of increasing the electricity market.In this paper, a mathematical morphology and genetic algorithm based dynamic reactive power optimization method for distribution network is proposed.By means of constructing mathematical morphology filter, the binary image composed by allelic genes of chromosome is filtered and the problem that deals with the action times of voltage regulating devices for compensation is turned into filtering problem of discrete binary image.With further automate scheduling, distribution automation and unmanned substation reactive power optimization of distribution line running made an urgent request.Reactive power optimization can improve the voltage passing rate, increasing the reliability of the system, the power quality, and the system runs the security and economy of the perfect combination, very broad application prospects.

In response to the difficulties in integrating high proportion distributed photovoltaic energy storage into active distribution network lines at present, this study proposes a novel multi period reconstruction and loss reduction model for active distribution networks with safety constrained optimal power flow. The method proposed by the research institute could effectively allocate reactive power output based on reactive power capacity, achieving better reactive voltage control. Nodes 2 and 3 with smaller reactive power capacity outputted 0.33Mvar, nodes 27 and 28 with medium capacity outputted 0.71Mvar, and nodes 16 and 17 with larger capacity outputted up to 0.98Mvar. This differentiated reactive power allocation strategy effectively optimized voltage control and ensured the stability of active distribution network lines. In addition, the annual system operating cost of the suggested method was reduced by 167889.33 yuan. From this, the suggested method demonstrates significant benefits in both economic and environmental aspects. It provides a practical and feasible optimization strategy for the high proportion of distributed photovoltaic energy storage connected to active distribution networks, which can promote the transformation of energy structure.

To improve the economy of offshore oil production platform shore‐based power transmission mode, the reactive power capacity allocation technology of offshore oil production platform shore‐based power supply system based on different network topology reliability measures was proposed. The optimization model of power supply system network topology and the structure model of voltage source converter high voltage direct current transmission system were established, the start and stop control scheme of flexible direct current (DC) transmission system was designed, and the operation parameters of converter station and DC line were monitored in real time. The topological structure of offshore oil production platform shore‐based power supply system is constructed, the mathematical model of flexible DC transmission system is established when the alternating current side voltage is balanced, the reactive power capacity configuration of offshore oil production platform shore‐based power supply system is optimized, and the life cycle cost results are calculated. The experimental results show that the algorithm proposed in this paper can obtain the optimal solution only after 26 calculations, with high optimization efficiency and good convergence effect. Reactive capacity configuration of shore‐based power supply system for offshore production platform can reduce failure rate and life cycle cost.

The reactive power is the background power without which the active power cannot be transmitted in the power systems. In the modern power system, the reactive power pricing is considered as essential in order to maintain the voltage in the transmission line. The modern power system is the grid that functions with smart innovative technological system that provides flexibility, efficiency and availability for the users. The smart grid uses the Internet of Things (IoT) technology to identify and provides the requirement of system reactive power for reactive power pricing. The IoT based wireless communication platform significantly reduces the latency and provides better accuracy. The system requirements for reactive power are optimally dispatched by the generator and other reactive power provider using optimization algorithm like Self Balanced Differential Evolution. Here the analytics and opportunities of smart grid for reactive power service are discussed using 62 bus Indian Utility System (IUS).

Existing standards impose limits on the allowable feeder voltage variation in a distributed generation environment. These stipulations must be respected by the distributed power generators (suppliers), which put a cap on the penetration level. A possible solution is to provide reactive power support to improve the voltage profile. This paper proposes a novel scheme, where an auxiliary circuit (comprising an inverter and reactive power bank, RPB), in conjunction with a PV-grid system, increases the system's reactive power compensation capacity up to 300% compared to the original or dedicated VAR capacity of the main PV inverter. In spite of using only the conventional discrete form of capacitor/inductor bank, the entire VAR range can be controlled. This enables the local Photovoltaic Distributed Generation System (PV-DGS) to provide the necessary reactive power support for the mitigation of large voltage variation on the feeder because of reverse power flow, intermittent solar radiation and load variation. This, in turn, supports increased PV penetration into the power system. As an extension of the proposed scheme, any existing conventional reactive power banks may be retrofitted with a given PV grid system to realize the proposed functionality. Detailed modeling, analysis and control design are included along with experimental verification.

The wind power generation system driven by a variable speed wind turbine is extensively studied for its ability of varying rotating speed to track the optimal TSR and the maximal energy capture when the wind speed is changed. Another advantage of the variable speed wind power generation system than a fixed-speed one is its capability of reactive power and voltage control. Doubly-fed induction generators are widely used in variable speed wind power generation systems, with a frequency converter connected between the grid and the rotor winding, which is used for match of variable speed and constant frequency. Additionally, the converter can act for reactive power and voltage control by feeding particular voltages on the rotor winding. Naturally, the rotor voltage may have simultaneous influence on both speed and reactive power of the generator, but the rotor voltage indeed has two freedoms. So, a decoupled control of speed and reactive power is developed in this paper, based on the nonlinear inverse system method, and simulation results show the validity of the proposed control law.

In distribution systems, the generation and transmission of reactive power over long distances are economically impractical. However, this study proposes an efficient solution to meet the demand for reactive power by strategically integrating capacitor banks at load centers. Distribution systems commonly face issues such as high power losses and poor voltage profiles, primarily due to low power factors resulting in increased current and additional active power losses. This article focuses on assessing the static effects of capacitor bank integration in distribution systems. The study involves the deployment of 3.42MVAr capacitor banks in 20kV, 4-bus-bar systems and 1.164MVar capacitor banks in 0.4kV, 2-bus-bar systems. The impact is thoroughly analyzed through measurements and pre/post-installation studies. Load flow analysis, conducted using Power World software for simulation modeling, predicts power flows, voltage levels, and active power losses across system branches. We draw a comprehensive comparison between distribution systems with and without capacitor banks, encompassing both technical and economic aspects. The evaluation includes power flow magnitudes, voltage profiles, and active power losses. The proposed approach offers numerous benefits, including power factor correction, reactive power support, reduced losses, and enhanced voltage profiles in the distribution system.

This paper proposes a hierarchical multi-stage approach based on a distributed level phasor measurement unit (µPMU) at local controllers and a phasor data concentrator (PDC) at the central control unit to restore system voltage when it exceeds the limits recommended by the IEEE 1547-2018 standard. The proposed algorithm does not need an accurate system model or employ optimization solutions. Therefore, it has less implementation complexity and would be popular among distribution network service providers (DNSPs) and distribution network operators (DNOs) as it does not suffer from cost and computational complexity limitations. A PMU-PDC-based communication platform has been developed as a more efficient alternative to the supervisory control and data acquisition (SCADA) system, and provides superior characteristics, including a higher sample rate, higher data resolutions, and faster communication. The proposed coordinated algorithm aims to postpone power generation curtailment in distributed energy resources (DERs) with overvoltage problems (local DERs) by incorporating all the DERs that are not subjected to voltage violation (remote DERs) by absorbing their maximum reactive power capacity. If the system voltage has not recovered after absorbing all of the reactive power capacity of all the DERs, a reduced active power curtailment proposed by the algorithm is then applied to the system to control the voltage. The proposed strategy has been simulated in MATLAB and applied to IEEE 13-bus and IEEE 33-bus radial distribution benchmark systems to validate the performance of the system, in terms of its ability to coordinate voltage control and the accuracy of the PMU-PDC-based communication interface.

This work aims to analyze the effects of a reactive power market on the operation of a power pool. For this, it proposes a reactive power generation cost function which is based on two facts: (i) the profit of a generation company depends on the amount of active power it sells to the market, and (ii) a generator's active power output is limited by its reactive power output. Thus, first of all, this work represents the active power generating capacity of a synchronous machine in terms of its reactive power output. Next, it associates the cost of lost opportunity to the cost of reactive power generation. This reactive cost function is introduced in a reactive optimal power flow model which is parameterized in its active and reactive loads. The solution to this problem is tracked, via a continuation method, until the maximum loadability limit. In this way, it is possible to analyze the influence of the reactive power costs on the maximum loadability limit and the market power of any generator at different load levels. Results are presented for different test systems.

When the brushless doubly-fed induction generator (BDFIG) connects to the power grid, the reactive power capacity of the BDFIG is an essential issue, especially when the grid voltage drops. In this paper, the active power and reactive power of the BDFIG are derived, the power region based on the power winding current and voltage, the control winding current and the rotor speed is analyzed, the capacity of absorbing the reactive power is constrained by the power winding stator current, while the output reactive power capacity of the BDFIG is dominated by the CW stator current. Furthermore, the gird-connected control method is developed, and the expected power is achieved. The simulation results verify the correctness of the control method and the reactive power tracking performance of the BDFIG.

Thermal power generators have both active power (AP) and reactive power (RP) requirement to meet up the total power demand. Considering the total power demand such generators supply the essential RP along with the AP. Consequently by considering the reactive power demand it is also an important to consider its cost along with the cost based on active power generation. In this paper, the generalised mathematical functions for the cost considering the RP are formulated and incorporated with the cost function based on active power generation. Particle Swarm Optimization (PSO) algorithm has been applied to solve Optimal power flow (OPF) problem (OPFP). The proposed work has been examined and tested on IEEE-9 bus system with different objectives such as total fuel cost based both active and reactive power generation, transmission losses, voltage profile improvement. The results drawn show its validity and effectiveness.