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With the deployment of sensor and communication network, the conventional power system is transformed into a multi-dimensional heterogeneous complex system, which is known as Cyber-Physical Power System (CPPS). On the one hand, CPPS has developed new abilities of real-time sensing, dynamic control and information services; on the other hand, massive information interaction in CPPS has posed more potential...
Virtual power plant(VPP) integrate distributed power, energy storage device and load, through reasonable control mode, the virtual power plant will have the same controllable external characteristics as the traditional power plant, such as maximum power generation capacity, minimum technical output, climbing rate, and frequency regulation characteristic etc. This paper presents a control strategy...
In smart grid, a strong communication network plays a very important role, which makes the power grid more controllable and observable. It is a very tough task to study the mutual impact between these two systems due to their different characteristics. This paper proposes a generic and systematic approach for quantitatively studying the impact of communication failures on power grid's measurement...
Image hiding is an important technique in information security field. The simplest method is the least significant bit (LSB) substitution method that embeds a secret image in the least significant bits of the pixels of a host image. The embedding idea is simple, but the embedding process may degrade the host image quality so much that a hacker’s suspicion may be raised. To improve the image quality...
Micro Gird Cluster (MGC), connecting to the medium or low voltage distribution network, usually contains certain number of Micro Grids, distributed generators, energy storages and loads. Considering coordinated operation in MGC, this paper proposes a hierarchical control architecture-the upper layer operated in distributed mode among multiple MGs and the lower layer were controlled by each micro grid...
The safe and reliable transmission of relay protection signal is essential to the normal operation of relay protection device. Based on the characteristics of the protection signal transmission, this paper proposes a method to model the real time failure rate of the protection communication channel introduced by the communication latency and bit error. First of all, by using the decision tree method...
The conventional automatic generation control (AGC) strategy only takes the economic factors into consideration. However, for interconnected power grids, under the condition of communication failure, there will be high risk that the AGC control signal be blocked and then some AGC units will not adjust the generating power following the load fluctuation due to the interrupt of the control signal. In...
A reliability assessment methodology for transmission line protection systems is presented, which is based on a probabilistic modeling of the protection system's successful operation, and considering both the availabilities of the line protection hardware and the failure function of the current differential protection caused by communication delay. The system successful operation is described by reliability...
In this paper, the mathematical method of the MIIF (multi-infeed interaction factor) under UHVDC hierarchical connection mode is analyzed, and the correctness of the method is verified by PSCAD simulation. In hierarchical connection mode, it was analyzed that one inverter in a bus which has been in the condition of commutation failure has effect on another inverter in another bus with the change of...
The paper studies the impact of power grid operation state and communication delay on current differential protection with a probabilistic method, and a false-trip probability model is proposed. First, the mechanism of false-trip of current differential protection is introduced and the quantitative relationship between differential current and power grid operation state and communication delay is...
The regional security and stability control system is an important tool to ensure the safe and stable operation of modern power system. The communication system can provide information exchange among the stations for the regional security and stability control. Hence, the reliability of communication system is one of the important factors that need to be considered in the design of the control system...
With the development of strong and smart grid, power grid and communication system become highly interconnected and mutually dependent. Complex network approach is applied in this paper to describe the interactive characteristics of hybrid power and communication systems in terms of topologies. Qualitative analysis of the impact of communication system on power grid is straightforward. However, quantitative...
Sparse representation for classification (SRC) has attracted much attention in recent years. It usually performs well under the following assumptions. The first assumption is that each class has sufficient training samples. In other words, SRC is not good at dealing with the undersampled problem, i.e., each class has few training samples, even single sample. The second one is that the sample vectors...
Ultra-high Voltage (UHV) grid will become the backbone of China's future strong and smart grid. However, some new problems have arisen, such as ultra-long haul communication for UHV grid. At present, Optical Fiber Composite Overhead Ground Wire (OPGW) is widely deployed for power communication system, and repeater stations are required for long haul communication. As the UHV lines usually cross over...
Traditional weighted least absolute value (WLAV) rubust state estimation based on interior point method (IPM) can improve the estimation accuracy by minimizing the impact of bad datas which is limited in practical application because of low efficiency. In this paper, a bilinear weighted least absolute value (WLAV) power system state estimation (SE) based on interior point method is proposed, where...
This paper proposes a risk evaluation model to assess the impact of communication delay and bit error on relay protection. First, the mechanism of mal-function of relay protection caused by communication delay and bit error is introduced. In general, a channel's consistent delay or bit error results in refuse-operation, while a channel's inconsistent delay normally causes false trip. Based on the...
Communication system provides technical support for observability and controllability of Wide-Area Power System. However, communication faults such as time delay. bit error and interruption may lead to abnormal operation, sometimes even causing cascaded failure in electric power system. Therefore. it is important to perform the vulnerability assessment of electric power and communication system in...
Due to the independence of the domain knowledge, general search engine has "theme drift" problem in the search of domain knowledge. Topic specific search engine offers a faster, and more accurate web resources retrieval service, and a good web page sorting algorithm can improve user experience. In this paper, we proposed a new sorting algorithm for topic specific search engine based on ontology...
This research proposes a systematic approach to identify critical assets that support the efficiency of electricity markets. NERC standards CIP provides guidance on the identification and protection of critical cyber assets that support the reliability of power systems. Those assets don't include properties that are critical to the efficiency of electricity markets. However, attacking such properties...
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