scholarly journals Mapping and Analysis of the Reactive Power Balance in the Danish Transmission Network

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 419
Author(s):  
Mads Nannestad ◽  
Zhe Zhang ◽  
Jundi Jia ◽  
Emil Jensen ◽  
Peter Randewijk
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Transmission System ◽  
Scale Model ◽  
Power Balance ◽  
Transmission Network ◽  
Power Devices ◽  
Comprehensive Overview ◽  
Overhead Lines ◽  
System Operator

This paper investigates the reactive power balance of the Zealand side of the Danish transmission system (DK2) by using QV-curves. The study is performed in cooperation with Energinet, who is the Danish transmission system operator (TSO). Firstly, this paper aims to map the reactive power balance with the current challenges in the system, which appears due to a decision of changing overhead lines in the scenic area to cables. Secondly, a method is derived for obtaining a comprehensive overview of the impacts that future projects might have on the system. By dividing the transmission system into smaller areas, it is possible to analyze how the reactive power will affect the voltage; moreover, it is favorable to analyze and handle the challenges in the reactive power balance locally. This helps the TSO to quickly determine the lack of reactive power devices and issues that might occur in future expansions of the system. For this paper, a full-scale model of DK2 and SCADA-data has been utilized. It covers the period from 01-01-2016 to 20-08-2017 between the TSO and the Distribution System Operator (DSO). The studies have shown how the location of the wind production will create issues in the reactive power balance.

scholarly journals Local Market for TSO and DSO Reactive Power Provision Using DSO Grid Resources

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3442
Author(s):  
Fábio Retorta ◽  
João Aguiar ◽  
Igor Rezende ◽  
José Villar ◽  
Bernardo Silva
Keyword(s):  
Real Time ◽  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Time Interval ◽  
Local Market ◽  
Distribution Grid ◽  
Power Profile ◽  
System Operator

This paper proposes a near to real-time local market to provide reactive power to the transmission system operator (TSO), using the resources connected to a distribution grid managed by a distribution system operator (DSO). The TSO publishes a requested reactive power profile at the TSO-DSO interface for each time-interval of the next delivery period, so that market agents (managing resources of the distribution grid) can prepare and send their bids accordingly. DSO resources are the first to be mobilized, and the remaining residual reactive power is supplied by the reactive power flexibility offered in the local reactive market. Complex bids (with non-curtailability conditions) are supported to provide flexible ways of bidding fewer flexible assets (such as capacitor banks). An alternating current (AC) optimal power flow (OPF) is used to clear the bids by maximizing the social welfare to supply the TSO required reactive power profile, subject to the DSO grid constraints. A rolling window mechanism allows a continuous dispatching of reactive power, and the possibility of adapting assigned schedules to real time constraints. A simplified TSO-DSO cost assignment of the flexible reactive power used is proposed to share for settlement purposes.

scholarly journals Reactive Power Management Considering Stochastic Optimization under the Portuguese Reactive Power Policy Applied to DER in Distribution Networks

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4028 ◽  
Author(s):  
Abreu ◽  
Soares ◽  
Carvalho ◽  
Morais ◽  
Simão ◽  
...  
Keyword(s):  
Power Management ◽  
Distribution System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Real Data ◽  
Distribution Networks ◽  
System Operator

Challenges in the coordination between the transmission system operator (TSO) and the distribution system operator (DSO) have risen continuously with the integration of distributed energy resources (DER). These technologies have the possibility to provide reactive power support for system operators. Considering the Portuguese reactive power policy as an example of the regulatory framework, this paper proposes a methodology for proactive reactive power management of the DSO using the renewable energy sources (RES) considering forecast uncertainty available in the distribution system. The proposed method applies a stochastic sequential alternative current (AC)-optimal power flow (SOPF) that returns trustworthy solutions for the DSO and optimizes the use of reactive power between the DSO and DER. The method is validated using a 37-bus distribution network considering real data. Results proved that the method improves the reactive power management by taking advantage of the full capabilities of the DER and by reducing the injection of reactive power by the TSO in the distribution network and, therefore, reducing losses.

scholarly journals Quantifying TRM by Modified DCQ Load Flow Method

2021 ◽  
Vol 23 (2) ◽  
pp. 157-163
Author(s):  
Awatif Nadia ◽  
Md. Sanwar Hossain ◽  
Md. Mehedi Hasan ◽  
Khondoker Ziaul Islam ◽  
Shahajan Miah
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Load Flow ◽  
Transmission Network ◽  
Distribution Factor ◽  
Electric System ◽  
Flow Method ◽  
Transmission Reliability ◽  
System Operator ◽  
Integrated Power System

In the integrated power system network uncertainty can occur at any time. The transmission reliability (TRM) margin is the amount of transmission capacity that guarantees that the transmission network is protected from instability in the operating state of the system. The calculation of the available transfer capacity (ATC) of the transmission reliability margin should be included in a deregulated power system to ensure that the transmission network is safe within a fair range of uncertainties that arise during the power transfer. However, the TRM is conserved as a reliability margin to reflect the unpredictability of the operation of the electric system. Besides, the system operator (SO) utilizes the TRM value during unreliability by adjusting the ATC value some amount up or down to account for errors in data and uncertainty in the model. This paper describes a technique for TRM estimation by modified DCQ load flow method considering VAR transfer distribution factor. The main focus of this study is to get a new approach to determine TRM by incorporating with ATCQ considered reactive power and sensitivity w.r.t ATC considered voltage magnitude. This technique is applied to the IEEE 6 bus system, and results are compared with previous results for validation. The technique leads to more exact and secure estimates of transmission reliability margin.

scholarly journals Compliance of Distribution System Reactive Flows with Transmission System Requirements

2021 ◽  
Vol 11 (16) ◽  
pp. 7719
Author(s):  
Panagiotis Pediaditis ◽  
Katja Sirviö ◽  
Charalampos Ziras ◽  
Kimmo Kauhaniemi ◽  
Hannu Laaksonen ◽  
...  
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Real Data ◽  
Distribution Networks ◽  
Transmission System ◽  
Distributed Energy ◽  
Medium Voltage ◽  
Power Set ◽  
System Requirements ◽  
Advanced Model

Transmission system operators (TSOs) often set requirements to distribution system operators (DSOs) regarding the exchange of reactive power on the interface between the two parts of the system they operate, typically High Voltage and Medium Voltage. The presence of increasing amounts of Distributed Energy Resources (DERs) at the distribution networks complicates the problem, but provides control opportunities in order to keep the exchange within the prescribed limits. Typical DER control methods, such as constant cosϕ or Q/V functions, cannot adequately address these limits, while power electronics interfaced DERs provide to DSOs reactive power control capabilities for complying more effectively with TSO requirements. This paper proposes an optimisation method to provide power set-points to DERs in order to control the hourly reactive power exchanges with the transmission network. The method is tested via simulations using real data from the distribution substation at the Sundom Smart Grid, in Finland, using the operating guidelines imposed by the Finnish TSO. Results show the advantages of the proposed method compared to traditional methods for reactive power compensation from DERs. The application of more advanced Model Predictive Control techniques is further explored.

Assessing the value and impact of demand side response using whole-system approach

2017 ◽  
Vol 231 (6) ◽  
pp. 498-507 ◽  
Author(s):  
Danny Pudjianto ◽  
Goran Strbac
Keyword(s):  
Distribution System ◽  
System Approach ◽  
Distribution Systems ◽  
Transmission System ◽  
Investment Model ◽  
Demand Side ◽  
Electricity System ◽  
System Operator ◽  
The Impact ◽  
Demand Side Response

This paper describes the whole-system based model called Whole-electricity System Investment Model to quantify the benefits of demand flexibility. Whole-electricity System Investment Model is a holistic and comprehensive electricity system analysis model, which simultaneously optimises the long-term investment decisions against real-time operation decisions taking into account the flexibility provided by demand. The optimisation considers the impact of demand side response across all power subsystems, i.e. generation, transmission and distribution systems, in a coordinated fashion. This allows the model to capture the potential conflicts and synergies between different applications of demand side response in supporting particularly intermittency management at the national level, improving capacity margin, and minimising the cost of electrification. The impact and value of demand side response driven by whole-system approach are compared against the impact and value of distribution system operator or transmission system operator centric (silo approaches) demand side response applications and the importance of control coordination between distribution system operator and transmission system operator for optimal demand side response is discussed and highlighted.

scholarly journals PV system reactive power coordination with ULTC & shunt capacitors using grey wolf optimizer algorithm

2020 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Mogaligunta Sankaraiah ◽  
S Suresh Reddy ◽  
M Vijaya Kumar
Keyword(s):  
Solar System ◽  
Objective Function ◽  
Distribution System ◽  
Distribution Systems ◽  
Reactive Power ◽  
Grey Wolf Optimizer ◽  
Grey Wolf ◽  
Power Devices ◽  
Shunt Capacitors ◽  
System Power

The presence of PV systems increases rapidly in distribution systems to improve reliability and quality of supply. This will influence the performance of under load tap changing (ULTC) transformer and related reactive power devices. Therefore, many researchers are working on this area. This paper main objective is to reduce switching operations of reactive power devices (ULTC and Shunt capacitors) together with system power loss.  Distribution system load and solar system power will predict one day in advance and grey wolf optimizer (GWO) algorithm proposed to solve the objective function. Reactive power of solar system is coordinated together with ULTC and shunt capacitors (SCs) with the aid of forecasted load. Distribution system losses and switching operations of ULTC and SCs converted into objective function in terms of cost. The proposed method is applied on practical 10KV system and the results are compared with conventional and particle swarm optimization (PSO) methods considering grid conditions.

Radial System Reconfiguration to Minimize Operating Costs in Markets

2007 ◽  
Vol 8 (1) ◽  
Author(s):  
S. Chandramohan ◽  
R. P. Kumudini Devi ◽  
Bala Venkatesh
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Operating Cost ◽  
Voltage Profile ◽  
Ancillary Service ◽  
Real Power ◽  
Sample Test ◽  
System Operator ◽  
Reliable Power Supply ◽  
Regulatory Commission

The operating cost of a radial distribution system may be minimized by reducing the amount of real power and reactive power drawn from the transmission system. Presently, real power is being priced through a market clearing scheme all over North America. Reactive power is an ancillary service and its supply would be priced appropriately in the near future through a clearing market structure. A recent US Federal Energy Regulatory Commission staff report [1] has initiated a discussion on the formulation of a reactive power market. When such a market is designed and operated, large customers (distribution corporations) will have to purchase reactive power along with real power from the transmission corporation through an independent system operator. Envisaging such a prospect, this paper proposes a new method of reconfiguring radial systems considering costs of real and reactive power while maintaining an appropriate voltage profile and level of reliable power supply. The proposed method is tested on sample test systems and reported.

scholarly journals An MPC-Sliding Mode Cascaded Control Architecture for PV Grid-Feeding Inverters

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2326 ◽  
Author(s):  
Alessandro Palmieri ◽  
Alessandro Rosini ◽  
Renato Procopio ◽  
Andrea Bonfiglio
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Sliding Mode ◽  
Renewable Energy Sources ◽  
Control Level ◽  
Operating Mode ◽  
Control Architecture ◽  
System Operator ◽  
Power Point ◽  
Control Theories

The primary regulation of photovoltaic (PV) systems is a current matter of research in the scientific community. In Grid-Feeding operating mode, the regulation aims to track the maximum power point in order to fully exploit the renewable energy sources and produce the amount of reactive power ordered by a hierarchically superior control level or by the local Distribution System Operator (DSO). Actually, this task is performed by Proportional–Integral–Derivative (PID)-based regulators, which are, however, affected by major drawbacks. This paper proposes a novel control architecture involving advanced control theories, like Model Predictive Control (MPC) and Sliding Mode (SM), in order to improve the overall system performance. A comparison with the conventional PID-based approach is presented and the control theories that display a better performance are highlighted.

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