Large Power System Interconnections Research Articles

Load Margin Assessment of Power Systems Using Physics-Informed Neural Network with Optimized Parameters

Challenges in the operation of power systems arise from several factors such as the interconnection of large power systems, integration of new energy sources and the increase in electrical energy demand. These challenges have required the development of fast and reliable tools for evaluating the operation of power systems. The load margin (LM) is an important index in evaluating the stability of power systems, but traditional methods for determining the LM consist of solving a set of differential-algebraic equations whose information may not always be available. Data-Driven techniques such as Artificial Neural Networks were developed to calculate and monitor LM, but may present unsatisfactory performance due to difficulty in generalization. Therefore, this article proposes a design method for Physics-Informed Neural Networks whose parameters will be tuned by bio-inspired algorithms in an optimization model. Physical knowledge regarding the operation of power systems is incorporated into the PINN training process. Case studies were carried out and discussed in the IEEE 68-bus system considering the N-1 criterion for disconnection of transmission lines. The PINN load margin results obtained by the proposed method showed lower error values for the Root Mean Square Error (RMSE), Mean Square Error (MSE) and Mean Absolute Percentage Error (MAPE) indices than the traditional training Levenberg-Marquard method.

PMU-Based Power System Stabilizer Design Using Coati Optimization Algorithm

Low-frequency oscillation modes can destabilize the power system if they do not have adequate damping rates. The interconnection of large power systems and the complexity of operation has caused the increase in these modes and conventional control techniques have difficulty guaranteeing adequate damping rates. This article proposes a design method for a Power System Stabilizer damping controller using data from Phasor Measurement Units (PMUs) to ensure adequate damping rates for the modes even in the event of PMU data failures. Case studies were simulated and analyzed using the IEEE 68-bus system.

Planning multi-terminal direct current grids based graphs theory

Transmission expansion planning in AC power systems is well known and employs a variety of optimization techniques and methodologies that have been used in recent years. By contrast, the planning of HVDC systems is a new matter for the interconnection of large power systems, and the interconnection of renewable sources in power systems. Although the HVDC systems has evolved, the first implementations were made considering only the needs of transmission of large quantities of power to be connected to the bulk AC power system. However, for the future development of HVDC systems, meshed or not, each AC system must be flexible to allow the expansion of these for future conditions. Hence, a first step for planning HVDC grids is the planning and development of multi-terminal direct current (MTDC) systems which will be later transformed in a meshed system. This paper presented a methodology that use graph theory for planning MTDC grids and for the selection of connection buses of the MTDC to an existing HVAC transmission system. The proposed methodology was applied to the Colombian case, where the obtained results permit to migrate the system from a single HVDC line to a MTDC grid.

Using Disturbance Data to Monitor Primary Frequency Response for Power System Interconnections

Insufficient frequency response can lead to balancing, control performance issues, and even reliability problems. This letter proposes a new method to evaluate the primary frequency response for large power system interconnections. This approach is evaluated using actual disturbance data from the Western Electricity Coordinating Council.

Feasibility Study of Segmenting Large Power System Interconnections With AC Link Using Energy Storage Technology

This paper studies the feasibility of segmenting large power system interconnections with AC link using energy storage technology, similar to the DC link, for improving the system dynamic stability. Firstly, the segmentation validity of the AC interconnected power system using energy storage technology is proved in terms of theoretical analysis, and then a simple and effective control strategy is proposed. Moreover, the influences of the energy storage device location and capacity on the proposed method are discussed in detail. The effectiveness of the proposed method for large AC interconnected power system segmentation is verified by simulations in two AC interconnected power systems.

Going the Distance

The transmission of bulk power over long distances is a very current topic in the worldwide energy sector. An excellent example is the transmission system of Madeira River Hydropower Generation Project in Brazil, which includes two 2,400-km transmission lines, designed to transmit 3,150 MW through each HVDC link. In fact, long transmission trunks enable the use of natural resources that are far from major load centers as well as provide the interconnection of large power systems.

General philosophy of emergency control in the UPG of the USSR

Large power system interconnections now cover vast areas of the developed countries of the world. For the economic and reliable operation of such complex networks, it is essential that adequate stability control measures are adopted in order to deal quickly and effectively with emergency situations. This paper describes the development and implementation of the automatic emergency control system used in the Unified Power Grid of the USSR.

The next step in interrupting capacity — 5,000,000 kva

Serious consideration is being given to large power-system interconnections which could develop short circuits at certain locations in excess of 3,500,000 kva. High-voltage oil-circuit-breaker capabilities for such heavy duty are reviewed in this paper, the fundamental design requirements outlined, and results of high-power laboratory tests presented which demonstrate that interrupting capacity ratings as high as 5,000,000 kva are feasible. Laboratory test methods for demonstrating these extremely high arc rupturing ratings are evaluated. The importance of verifying high-speed reclosing performance with high-power tests is emphasised, and on the basis of data already obtained, standard reclosing time intervals considerably less than 20 cycles are foreseen.

The next step in interrupting capacity-5,000,000 Kva

Serious consideration is being given to large power-system interconnections which could develop short circuits at certain locations in excess of 3,500,000 kva. High-voltage oil-circuit-breaker capabilities for such heavy duty are reviewed in this paper, the fundamental design requirements outlined, and results of high-power laboratory tests presented which demonstrate that interrupting capacity ratings as high as 5,000,000 kva are feasible. Laboratory test methods for demonstrating these extremely high arc rupturing ratings are evaluated. The importance of verifying high-speed reclosing performance with high-power tests is emphasized, and on the basis of data already obtained, standard reclosing time intervals considerably less than 20 cycles are foreseen.

A New Frequency Relay for Power-System Applications

THE interconnection of large power systems with industrial and defense plants having a comparatively small generating capacity is not unusual in these days. These plants require a considerable block of power for 24-hour full-capacity operation, and this power is available by means of the interconnection with the power system. More than one interconnection would assure higher continuity of service, but the general practice of locating defense plants in rural or suburban areas, remote from urban power-system networks, often results in one transmission-line interconnection operating in parallel with plant generators. Like all lines, the interconnection is subject occasionally to faults with resulting temporary loss of power for the plant. During these emergencies, the local generator or generators at the plant which normally contribute to the total load are suddenly called upon to carry all of the plant load. The local generators are not able to supply this load and consequently are heavily overloaded. As a result, the frequency decreases rapidly. However, complete shutdown of the plant can be avoided by dropping some of the load and retaining within the capacity of the local generators the load of the most essential machines and processes.

A new frequency relay for power-system applications

THE interconnection of large power systems with industrial and defense plants having a comparatively small generating capacity is not unusual in these days. These plants require a considerable block of power for 24-hour full-capacity operation, and this power is available by means of the interconnection with the power system. More than one interconnection would assure higher continuity of service, but the general practice of locating defense plants in rural or suburban areas, remote from urban power-system networks, often results in one transmission-line interconnection operating in parallel with plant generators. Like all lines, the interconnection is subject occasionally to faults with resulting temporary loss of power for the plant. During these emergencies, the local generator or generators at the plant which normally contribute to the total load are suddenly called upon to carry all of the plant load. The local generators are not able to supply this load and consequently are heavily overloaded. As a result, the frequency decreases rapidly. However, complete shutdown of the plant can be avoided by dropping some of the load and retaining within the capacity of the local generators the load of the most essential machines and processes.

An Automatic Oscillograph

AS A RESULT of the new e ra of extensive interconnection of large power systems and of t he high speed operation of switches and circuit breakers, problems have arisen that only an oscillograph can solve; further an oscillograph for such applications must have characteristics that are not found in those designed for more general usage.