Cyclic Verification Method of Security Control System Strategy Table Based on Constraint Conditions and Whole Process Dynamic Simulation

This article research on the DC access grid security and stability analysis. It combed the stability and security of electrified weak link, revealing the power grid dynamic characteristics of evolution mechanism. It study and formulation of reservoir in the power grid security and stability control strategy of DC power transmission system, the access of power grids in Tibet, AC / DC hybrid power grid by the end of security and stability control measures. The conclusion of the study, for reservoirs in AC DC hybrid power grid by the end of the safe and stable operation and control measures for reference to make the reasonable.

In the summer peak load operation mode of the interconnected power grid which is integrated with HVDC transmission lines from Central China power grid to East China power grid, security and stability emergency control strategies based on generator shedding and EDCPS (Emergency DC Power Support) are studied to cope with system instability caused by Tuanlin-Fengjing DC line unipolar block fault. Simulation results show that interconnected system cannot maintain the transient stability effectively by using EDCPS only. A coordinated control strategy which combines generator shedding with EDCPS is proposed to reduce the number of generators to be shed and ensure the transient stability. Through optimizing EDCPS which two or more HVDC lines participate in, an optimal coordinated control strategy is proposed. Simulation results present that the strategy which combines GC shedding with Longzheng DC bipolar supporting is the optimal strategy.

Short-term frequency instability is one of the major concerns in power systems with high percentage of converter-interfaced renewable energy sources. Energy storage system (ESS) has proven to be a viable solution for the problem of short-term frequency instability by fast frequency response (FFR). However, the appropriate location, size, and operating strategy of ESS are the main challenges for FFR. Power injection at some buses in large grids may lead to angular separation and instability. In addition, oversizing ESS could lead to huge investments without appropriate returns and under sizing may jeopardizes grid stability. Capacity estimation of ESS for FFR considering the suitable location and overall deployment strategies are missing in the current literature for large power grids. Hence, this research proposes a technique to place and size ESS for better FFR in power grids. The proposed technique consists of two steps. In the first step, a methodology based on frequency dynamic signature (FDS) is developed to identify the most suitable location. In the second step, the required capacity of the ESS is estimated based on a step reduction iterative algorithm (SRIA). SRIA and FDS consider the complete dynamics of power system components that affect the frequency dynamics of the system. The proposed methodology is thoroughly verified for various operating conditions in IEEE 39-bus using DIgSILENT PowerFactory.

With the integration of large scale wind power, the characteristics of power system operation has been changing, and, some problems come forth. On-line security assessment and control decision support system provides the stability and security state message for dispatcher in time, and, some suggestions to improve the level of power system stability and security. To suit the requirements of large amount wind power integrated power system, the technology of on-line security assessment and control decision support must be modified. This paper focuses on the technology of on-line security assessment and control decision for operation of power system with large scale wind power and designing the support system. In the paper, the study and application of on-line security assessment and control decision support technology in China are introduced. Considering the wind power in China having some distinct characteristics such as large scale, centralized development, long-distance and high voltage transportation, the new requirements to on-line security assessment and control decision support are analyzed. They includes need for new information, on-line modelling with large scale wind farm, transfer limitation calculation under the constraint condition of wind power integration requirement, auxiliary preventive control decision based on the forecasting and adjustment properties of wind power output, coordinated emergency control wind power with hydraulic and thermal power. On the basis of technical rule for connecting wind farm into power grid and the interaction between wind power and power grid, the advices on engineering application of on-line security assessment and control decision support technology for large amount wind power integrated power system, are proposed, for example, with respect to the standard of security assessment and selection of pre-contingency sets. (7 pages)

Analyzing performance of security and stability control system is of great importance for the safe and stable operation of the power grid. Digital dynamic experimental model is built by real time digital simulation (RTDS) in order to research security and stability system of Inner Mongolia in northern 500kV transmission channel. The whole process is closed-loop dynamic real-time simulation. According to power grid network testing technology standard, all kinds of stability control devices need to be tested in a comprehensive system. Focus on the following items: security and stability control strategy, tripping criterion as well as power system low frequency oscillations. Results of the trial indicated that the simulation test platform based on RTDS have the ability of detecting the safe and stable device. It can reflect the action behavior and control characteristics of the safe and stable device accurately. The device can be used in the case of low frequency oscillation of the system.

Renewable energy generation has different static and transient characteristics than traditional synchronous power plants. The connection of renewable energy to the grid will have varying degrees of impact on the voltage stability of the local power grid. In a power grid with large renewable energy penetration, in addition to the voltage stability problem, renewable energy integration changes the original power flow distribution, line transmission power and inertia of the entire system, the power system transient stability has undergone tremendous changes. Renewable energy power generation technology and grid-connected scale are developing rapidly. The technical requirements for renewable energy and the research on grid-connected technology need to be continuously deepened and improved. However, some large-scale renewable energy off-grid accidents in recent years have brought serious threats to the security and stability of power systems, and have also raised higher research requirements for the stability of large-scale renewable energy grid-connected. This paper provides an introduction about the control and stability of renewable energy grid integration on both technologies and standardization aspects, and tries to explore potential the trend in active power and frequency control, reactive power and voltage control, security and stability control respectively caused by the integration of RE generation into power systems.

Since the security and stability control strategies (SSCSs) play a pivotal role in maintaining system stability, devising the strategies accurately and reliably is of great significance. Currently, SSCSs are typically formulated according to the ‘offline simulation and online matching’ approach. However, existing commercial simulation software is difficult to simulate the dynamic triggering mechanisms and intricate control logic of SSCSs. To simulate the set of SSCSs systematically and comprehensively, this paper has proposed an event-driven approach for simulations. Firstly, the SSCS is modeled as an event-driven model containing three elements: event, event listening, and event processing. Then, on the basis of the event triggering mechanism presented in this paper, the complex control logics of SSCSs, such as the prioritization of tripping generators, are implemented. Through event-driven models of SSCSs and subsequent utilization of the event-triggered mechanism, independent and dynamic responses of SSCSs can be realized, thus avoiding interference in the simulation of multiple SSCSs. Finally, the effectiveness of the proposed method is verified based on the IEEE 39-bus system.

In the modern society with a high dependence on power systems, the stable operation of the power grid is of utmost significance. Traditional approaches for analyzing power grid stability suffer from several limitations, including high computational complexity, notable sensitivity to data quality, and inadequate representation of dynamic characteristics. To address these issues, this paper proposes a power grid stability analysis method predicated on the Convolutional Neural Network (CNN). In this method, the discrimination of power grid stability is modeled as a binary classification problem. By performing preprocessing operations on the input data, such as outlier cleansing based on the 3 criterion and min-max normalization, the CNN's convolutional layers, pooling layers, and fully connected layers are utilized to extract features and classify the states. The case study is founded on the actual monitoring data of a regional power grid. The results demonstrate that the accuracy of the proposed method on both the training set and the test set is remarkably superior to that of the Fully Connected Neural Network (FNN). This method can offer effective technical support for the safe operation of the power grid.

In the context of the rapid development of digital education, the security of educational data has become an increasing concern. This paper explores strategies for the classification and grading of educational data, and constructs a higher educational data security management and control model centered on the integration of medical and educational data. By implementing a multi-dimensional strategy of dynamic classification, real-time authorization, and secure execution through educational data security levels, dynamic access control is applied to effectively enhance the security and controllability of educational data, providing a secure foundation for data sharing and openness.

Object-oriented logic configuration platform design for large power grid security and stability simulation

Under the "dual-carbon" target vision, the construction of a new power system with a gradually increasing proportion of new energy has become a major direction. In the process of the continuous development of the power system, the new energy has the characteristics of large volatility and strong randomness, so it is necessary to constantly improve the regulation capacity of the power grid to ensure the stability of the power system. In this paper, the hardware reliability of the security and stability control system is detected by quantitative calculation. Based on two different operation modes of "one out of two" and "two out of two", we use Markov state-space method to calculate the rejection probability respectively, with the ratio of the device repair rate and the fault rate being the parameters. The calculation results are used to analyze the stability of the system, which guarantees the stable operation of the power grid.

We introduce an innovative solution approach to the challenging dynamic load-shedding problem which directly affects the stability of large power grid. Our proposed deep Q-network for load-shedding (DQN-LS) determines optimal load-shedding strategy to maintain power system stability by taking into account both spatial and temporal information of a dynamically operating power system, using a convolutional long-short-term memory (ConvLSTM) network to automatically capture dynamic features that are translation-invariant in short-term voltage instability, and by introducing a new design of the reward function. The overall goal for the proposed DQN-LS is to provide real-time, fast, and accurate load-shedding decisions to increase the quality and probability of voltage recovery. To demonstrate the efficacy of our proposed approach and its scalability to large-scale, complex dynamic problems, we utilize the China Southern Grid (CSG) to obtain our test results, which clearly show superior voltage recovery performance by employing the proposed DQN-LS under different and uncertain power system fault conditions. What we have developed and demonstrated in this study, in terms of the scale of the problem, the load-shedding performance obtained, and the DQN-LS approach, have not been demonstrated previously.

The quality of power system operating need to assess maturity of small oscillation stability issues of regional power grid thoroughly, analysis level of operating, controller installation allocating and parameter optimization scheme from different develop stage of regional power grid accurately. The assessment scheme is based on damping torque analysis of real large scale power system. Small oscillation stability is to be evaluated through the mechanism of damping torque analysis with automatic voltage regulator and other power system stabilizers. By analyzing the characteristic of the link between damping torque provided or transferred through each generator and the oscillation mode detected in the power system, the maturity indice has been established. This indice may cover the information of the contribution of controllers towards the power system and the dispatching within each generator in power system. Practical application effects in a real large scale power grid indicates this assessment can thoroughly describe the action of control elements in the power grid, help to depict the whole picture of impact applying power system controllers. A novel maturity evaluation of small oscillation in power grid is presented.

In the modern new power grid, it is no longer a single voltage level, but a complex large power grid composed of AC and DC and multiple voltage levels, in which 800kV DC transmission project is the main artery of the large power grid, in the operation and management of the new large power grid, green safety vertical is its core pillar, If there is a forest fire in the transmission line corridor, it is likely to cause a tripping fault, especially for the ultra-high voltage DC transmission lines. The conductor insulation on the line will be damaged by the fire at a height of tens of meters above the ground, causing the power grid to trip. What causes this? The research group has concluded through big data analysis and multi-dimensional analysis that the “hot air column” of the forest fire is the main reason for destroying the external insulation of the ultra- high voltage DC transmission lines. The theory of the hot air column (i.e. the column theory) is extremely easy to destroy the external insulation characteristics of the power grid.

SSC (security and stability control) system is an important facility to ensure the security and stability operation of the power grid and improve the transmission capacity. However, the differentiation of power grid characteristics and the resulting diversity of stability control strategies determine that it is difficult to standardize the stability control system, and the stability control strategy is superimposed. In the process of machine realization, the degree of automation is not high, and personalized programming leads to hidden faults that are difficult to find through conventional means. Therefore, this paper proposes an automatic realization method of SSC code based on activity diagram. First, it sorts out the basic element configuration of SSC strategy and analyzes the relationship between them. Then summarized four procedures of SSC strategy implementation, using a unified description method of the SSC strategy to associate SSC model with the strategy code of SSC device, using standardized model analysis and code Generate tools to automatically generate device codes for SSC strategies. Finally, an engineering example is given, which uses automatic code generation tools to analyze and verify the correctness of the model and the practicability of the code.