This work presents a new coordinated operation (CO) framework for electricity and natural gas networks, considering network congestions and demand response. Credit rank (CR) indicator of coupling units is introduced, and gas consumption constraints information of natural gas fired units (NGFUs) is given. Natural gas network operator (GNO) will deliver this information to an electricity network operator (ENO). A major advantage of this operation framework is that no frequent information interaction between GNO and ENO is needed. The entire framework contains two participants and three optimization problems, namely, GNO optimization sub-problem-A, GNO optimization sub-problem-B, and ENO optimization sub-problem. Decision sequence changed from traditional ENO-GNO-ENO to GNO-ENO-GNO in this novel framework. Second-order cone (SOC) relaxation is applied to ENO optimization sub-problem. The original problem is reformulated as a mixed-integer second-order cone programming (MISOCP) problem. For GNO optimization sub-problem, an improved sequential cone programming (SCP) method is applied based on SOC relaxation and the original sub-problem is converted to MISOCP problem. A benchmark 6-node natural gas system and 6-bus electricity system is used to illustrate the effectiveness of the proposed framework. Considering pipeline congestion, CO, with demand response, can reduce the total cost of an electricity network by 1.19%, as compared to −0.48% using traditional decentralized operation with demand response.
Tree pruning is a very important work in forestry production, which plays an important role in the growth and lumber of trees. In the general environment of automatic production of machinery, the market urgently needs a robot that can realize pruning work to replace a large amount of manual labor and increase the economic benefits of forests. In this paper, a tree-climbing and pruning robot with simple operation and automatic climbing function suitable for trimming a variety of trees is designed. The climbing mechanism of the robot adopts an enveloping wheel climbing structure, and the wheels are installed obliquely to achieve spiral ascent. The pruning mechanism adopts a combination of a mechanical arm and a saw blade, which can change the pruning method according to actual work requirements.
In the tree-climbing robot, the sawing module is lifted and lowered by the planetary roller lead screw, so the dynamic analysis of the planetary roller lead screw is very important. In this paper, the stiffness of the mechanical joint of planetary roller lead screw is calculated according to the fractal theory, and the stiffness calculation formulas between roller and ring gear, roller and lead screw are obtained. In the dynamic simulation, the stiffness of each contact pair is set according to the formula, and two groups of models with consistent and inconsistent roller contact stiffness are established. The first six order modal analysis results of the two groups of models are compared, and the influence of uneven roller contact stiffness distribution on the whole planetary roller lead screw is obtained.
The regional energy system (RES) is a system that consumes multiple forms of energy in the region and achieves coordinated and efficient utilization of energy resources. The RES is composed of multiple micro energy systems (MESs); however, due to the mismatch of energy resources and different energy consumption within each MES, a large amount of clean energy is wasted, and each MES has to acquire extra energy. This significantly increases operation costs and contributes to environmental pollution. One of the promising ways to solve this problem is to deploy an energy storage system in the RES, which can make use of its advantages to transfer energy in space-time and fulfill the demand for loads in different periods, and conduct unified energy management for each MES in the RES. Nevertheless, a large number of users are deterred by the high investment in energy storage devices. A shared energy storage system (SESS) can allow multi-MESs to share one energy storage system, and meet the energy storage needs of different systems, to reduce the capital investment of energy storage systems and realize efficient consumption of clean energy. Taking multiple MESs as the object, this paper proposes a model and collaborative optimal strategy of energy management for the RES to accomplish high utilization of clean energy, environmental friendliness, and economy. First, the paper analyzes the internal energy supply characteristics of the RES and develops a model of the RES with an SESS. Then, the paper poses the management concept of load integration and unified energy distribution by using the operational information of each subsystem. An optimal operation strategy is established to minimize daily operation costs and achieve economic, environmentally friendly, and efficient operation of the RES. Third, by setting up scenarios such as no energy storage system and an independent energy storage system (IESS) of each MES and SESS, a case of a science and education park in Guangzhou, China, is illustrated for experiments. Numerical experiment results show that with an SESS built by the investor in the RES and applying the mentioned energy management strategy, the utilization of clean energy can be 100%, the operation costs can be reduced by up to 9.78%, the pollutant emission can be reduced by 3.92%, and the peak-to-valley difference can be decreased by 20.03%. Finally, the influence of energy storage service fees and electricity tariffs on daily operation costs is discussed, and the operation suggestions of the SESS are proposed. It validates the effectiveness of the proposed strategy.
Microgrids consider adjustable loads in demand-side management (DSM), which respond to dynamic market prices. A reliable DSM strategy relies on load forecasting techniques in day-ahead (DA) scheduling. This paper applies an error-driven prediction modulation to evaluate these differences. In addition, this paper creates two new DSM methods with an evaluation environment to utilize this modulation. The first method adds this modulation directly to traditional microgrid DSM with electrical storage. The second method creates two virtual sub-storages for behavior adjustment in both DA and real-time (RT) markets. The results of numerical studies indicate that the new DSM methods can reduce microgrid operation costs. INDEX TERMS Storage, microgrid, power market deregulation, behavior, smart grid, virtual storage.
The Anninghe fault forms the eastern boundary of the Sichuan‐Yunnan block in Southwest China and has been identified as an earthquake gap zone. This study intends to construct the upper crustal shear wave velocity (Vs) structure beneath the Anninghe fault to understand its seismotectonics and potential large earthquake hazards. We deployed a dense seismic array along the southern central Anninghe fault valley. From the 3‐month continuous records, we calculated vertical‐component cross‐correlation functions (CCFs). However, the surface wave signals in the CCFs are intensely interfered by near zero‐time‐lag noise. We proposed a mode separation method based on the high‐resolution linear Radon transform, which suppressed the interfered noise and greatly enhanced the surface wave signals for ambient noise tomography of the Vs structure. The fine upper crustal structure reveals a distinct narrow low‐velocity belt within a depth of 3 km beneath the Anninghe fault zone. At deeper depths (4.5–8 km), the narrow low‐velocity belt shifts to the east and correlates with the distribution of local earthquakes. Combining previous results with our new findings, we presented a seismotectonic model of the southern central Anninghe fault, which interprets the narrow low‐velocity belt as a water‐contained fracture zone that forms a seismogenic zone at deeper depths under transpression. In addition, we demonstrated through scenario earthquake simulations that fine structures play a significant role in the assessment of earthquake hazards along the Anninghe fault. As such, this study provides a typical window into seismotectonics and large earthquake hazards in the active southeastern Tibetan Plateau.
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