136results about How to "Improve the level of safe and stable operation" patented technology

The invention discloses an electric power system transient state stable real-time emergency control method based on relative kinetic energy. By means of the method of judging rotative speed difference-power angle difference variation tendency, the transient state stability of the system is monitored in real time to serve as a start-up condition of emergency control. When the fact that the system loses the power angle stability is judged, a remaining accelerating area is calculated based on the relative kinetic energy in a two-machine system, and a generator tripping value is calculated and controlled through the equal-area criterion. During the control decision process, the action delay time is taken into consideration, and the calculation results are enabled to be more reliable. The electric power system transient state stable real-time emergency control method based on the relative kinetic energy overcomes the defects that when an offline calculation is conducted, operation modes and obstructions need to be anticipated, and the flexibility is insufficient when a small probability accident is handled, and can be complementary to a security and stability control system, a new defense line is built to prevent the system from deteriorating further even causing a big blackout accident, the power grid safety and stability defense system is enriched, and the safety and stability operation level of the electric power system is improved.

The invention provides a stable, real-time and emergent voltage and power angle control method based on a response message. The method comprises steps as follows: step 1, a power angle quantity and a rotation speed quantity of an electric generator in an electrical power system as well as voltage and current amount of an important load bus of a receiving system are acquired in real time; step 2, power angle stability and voltage stability of the system are monitored in parallel simultaneously, the step 3 is executed when the system loses the power angle stability, the step 4 is executed when the system loses voltage stability, and the step 1 is executed when the system is stable; step 3, a retardation area Sc which should be increased to the system is calculated by utilizing a fit power characteristic curve, a generator-shedding measurement amount is determined, and the step 1 is executed; and step 4, the bus voltage amplitude is used as an evidence for judging the severity of voltage instability, the bus load shedding amount is determined according to the difference of the severity of voltage instability, and the step 1 is executed. The provided real-time and emergency control method adopts a parallel judgment manner, so that a stable, real-time and emergency control scheme of voltage and the power angle of an electrical power system is constructed.

The invention provides a safe method for entering tangent tower equal potentials for live-wire operation in 660kV direct current lines. First, an operator, wearing complete shielding clothing, climbs a tower from the ground to the position where a tower body and a conducting wire are at the same level. During the climbing process, the operator keeps a distance of 4.5-7.0 meters from an electrified body; second, the operator arrives at a high electric field from the towel body by an insulating carrier and the sum of the distance between a grounding body and the operator and the distance between the operator and the electrified body is kept between 4.6 meters and 7.0 meters; and the operator, when arriving at the electrified body, keeps a distance of 4.5-7.0 meters from the grounding body. The safe method can provide high safety for operators during the process of entering the tangent tower equal potentials in the 660kV direct current transmission lines for live-wire operation which therefore can be safely and conveniently conducted so as to improve the safe and stable operation level of the transmission lines.

The invention provides a transient stabilization control method for an interconnection electrical network after impact disturbance. The method comprises: based on the transient energy function of the electrical network after the impact disturbance, establishing, according to the energy propagation characteristic of the power fluctuation of a junctor, a junctor cut set potential energy function; through a junctor cut set potential energy curve and the angular phase difference of the busbars at the two ends of the junctor, predicting the angular phase stability of the interconnection electrical network; and calculating the power for removing a unit when there is power angle instability. The method provided by the invention can be applied to the theoretically and simulation analysis of an electric power system. By using the method, the propagation characteristics of transient energy in the electrical network after the impact disturbance can be mastered, the stability of the interconnection electrical network can be predicted, and a controlled variable for maintaining stability can be calculated, thus effective measures can be taken by analysis personnel, and the safe and stable operation level of the electric power system can be improved.

The invention discloses a method for evaluating the new energy acceptance capacity of a grid-connected point by comprehensively considering the stability characteristic, and belongs to the technical field of automation of power systems. The influences of wind power generation variability and instability on a power grid, an external load level and the change condition thereof are combined; a multi-machine system is equivalent to a single-machine infinite bus system through an EEAC method by employing a static stability constraint, reactive power control and a transient constraint of the power system as conditions; the stability margin and the sampling yield are calculated; and the capability of connecting a wind power station of considering a transient stability constraint to the power grid to the maximum extent is evaluated by employing the specified range of the sampling yield as an index. By the method, the safe and stable operation level of the wind power station can be improved; the generating capacity of the wind power station is effectively ensured; and the benefits of energy conservation and emission reduction are improved.

The invention relates to a method for power network splitting and load shedding. The method is characterized by the following splitting: low slip frequency splitting, high slip frequency splitting, low frequency overload splitting and splittings for alternative directions or ground fault. In addition, the splitting with a multi-round load shedding is carried out according to the received electrical power. The method of the invention can be employed to improve level of safe and stable operation of a self-propelled power system and a main network power system.

The invention provides a method for judging power angle instability and voltage instability based on the dynamic Thevenin equivalence. When a power system fails and instable, and the voltage is greatly reduced, the system operation and analysts is difficult to judge whether the instable property of the system belongs to the power angle instability or the voltage instability. Based on the dynamic Thevenin equivalence method, the real-time variation of the Thevenin equivalent potential of a load node to be monitored after the failure occurs can be obtained; and compared with the Thevenin equivalent potential, the instable property of the system can be judged. The method can be applied to the on-line analysis control and the off-line emulation analysis of the power system, facilitate the system operation and the analysts to adopt the effective measure in time and improve the safe and stable operation level of the power system.

The invention discloses an analysis experimental device and an analysis experimental method for protection malfunction caused by direct current (DC) grounding. The analysis experimental device stimulates the circuit sate of a DC system in actual operation, provides experimental parameters such as insulation resistance, bridge resistance, grounding capacitance, cable capacitance and the like, and can be used for experimenting on faults of positive grounding, negative grounding and control loop grounding; concrete experimental contents and a concrete experimental method are provided; and a principle of protection malfunction caused by one-point grounding and related parameters thereof are fully realized for research and development, production, inspection, operation and maintenance and other links so as to take protection measures to prevent the generation of protection malfunction accidents caused by one-point grounding, thereby effectively improving the safe operation level of an electric system. The experimental method can be widely applied in relay protection research and production manufacturers, DC grounding detection equipment research and production manufacturers and operation accident analysis on the electric system.

The invention provides a mathematical modeling method for steady-state random power fluctuation of an alternating current connecting line. Power grids are interconnected through the alternating current connecting line, and under the steady-state condition, long-cycle and irregular random power fluctuation on the connecting line is caused by load random fluctuation in the power grids at two ends. Based on a two-area alternating current connecting line power fluctuation model, according to the steady state operation and weak connecting line characteristics of large area power grids, a relation between the random power fluctuation and the power angle difference of equivalent generators is established, and a steady state random power fluctuation mathematical model of a two-area connecting line is obtained by solving a second-order differential equation of the power angle difference of the equivalent generators. The mathematical modeling method is applicable to theoretical and simulation analysis of a power system, the dynamic characteristic and connecting line random power fluctuation mechanism of two large-area interconnection power systems are mastered, the maximum amplitude of the steady-state random power fluctuation is computed, the system can conveniently operate, an analyst can timely take effective measures, and the safety and steady operation level of the power system is improved.

The invention discloses a construction method and an air conditioner control method for a multi-load joint control strategy, and belongs to the technical field of multi-load joint control strategies. According to an existing control strategy, flexible loads cannot be effectively scheduled and accurately controlled. According to the construction method for a multi-scene multi-load joint control strategy provided by the invention, multi-load response potentials are evaluated, and a reasonable power utilization plan is made according to load characteristics and market response characteristics represented by an evaluation result; a multi-micro-load aggregation model in multiple scenes is further established, and multi-load active response and coordinated optimization are achieved; and the multi-micro-load aggregation model in multiple scenes is used as a part of a combined optimization model of multi-micro-load regional operation scheduling, and multi-scene multi-load joint control is realized. Therefore, hierarchical flexible optimization operation and efficient scheduling of user-side multi-micro-loads are realized, and the dynamic balance capability of a power grid is improved.

Disclosed is an ultrahigh-voltage direct-current (DC) transmission project converter transformer alternating-current (AC) loop system on-site inspection method. The method is implemented on a converter transformer after installation and commissioning test, and a converter valve is installed and is always in a locked state. An AC 500kV GIS is removed temporarily to a drainage line of the converter transformer, a test converter transformer T is connected, a test voltage is applied to the AC network side of the converter transformer through the converter transformer T, the valve-side windings of a Y/Y converter transformer and a Y/Delta converter transformer are grounded, and whether there is a loop defect from the primary wiring to the secondary loop of the converter transformer is judged by detecting the amplitudes and phases of the primary test current, primary test voltage, secondary current and secondary voltage. The design, construction and commissioning quality of a converter transformer AC loop system can be detected comprehensively, and the level of safe and stable operation of DC transmission can be improved.

The invention relates to a method for entering a 500kV common-tower double-circuit vertically-arranged compact transmission line equipotential. A tower comprises a tower head and a tower body. The tower head comprises a tower window and a cross arm arranged on the top of the tower window. A wire is arranged in the tower window. A live-working person climbs the tower, reaches the position with the height equal to that of the wire, moves to the bottom end of an insulator in the tower window from the edge of the tower window in parallel, and reaches the wire equipotential. By the adoption of the method for entering the 500kV common-tower double-circuit vertically-arranged compact transmission line equipotential, the live-working person has high safety in the process of 500kV common-tower double-circuit vertically-arranged compact transmission circuit live working.

The invention provides a steady state voltage sensitivity determination method and apparatus for a half-wavelength electric transmission line. Parameters of the half-wavelength electric transmission line are collected firstly; then a steady state voltage model of the half-wavelength electric transmission line is established according to the parameters of the half-wavelength electric transmission line; and finally, the voltage sensitivity is determined according to the steady state voltage model of the half-wavelength electric transmission line. According to the technical scheme provided by the invention, by virtue of the steady state voltage model of the half-wavelength electric transmission line, the steady state voltage sensitivity of the half-wavelength electric transmission line is calculated; a relation among the voltage of the half-wavelength line along the line, load active power, load reactive power and system frequency change can be reflected; and the determination method and apparatus can be used for theoretical and simulation analysis of the half-wavelength power transmission system, and operation and control of the actual half-wavelength line, system operation and effective control measures adopted by analyzers can be promoted, and safe and stable operation level of the power system can be improved.

The invention discloses a new energy penetration rate assessment method based on probability power flow calculation, and belongs to the technical field of power system automation. The method combines the impact on a power grid from the variability and instability of wind/solar hybrid generation and the external load level and the change condition thereof. The method takes static stable constraint and reactive power control of a power system as conditions, obtains the change range of the voltage of an output common grid-connected point of a wind/solar hybrid generation station through probability power flow calculation, takes the specified range of the voltage of the grid-connected point as the index, and carries out the assessment of the maximum capability that the wind/solar hybrid generation station is connected to the power grid. The method can improve the safe and stable operation level of the wind/solar hybrid generation station, effectively guarantees the generation of the wind/solar hybrid generation station, and improves the energy-saving and emission reduction benefits.

The invention discloses a stability control device operation information system and an online power grid risk assessment method thereof. The system comprises a main controller, a data acquisition module, a centralized monitoring module, a real-time alarm module, an operation management module and an early warning decision module which are connected. The data acquisition module is used for acquiring actual measurement information of the stability control device, the centralized monitoring module is used for centralized monitoring of measured information of the stability control device, the real-time alarm module is at least used for event alarm of the stability control device and/or alarm of data inconsistency and/or insufficient control quantity, the operation management module is at leastused for constant value management and/or abnormal processing and/or action management of the stability control device, and the early warning decision module is used for current stability control strategy aided decision and/or online power grid risk assessment. According to the invention, an electric power safety accident level risk on-line assessment function possibly triggered by load sheddingdue to the action of the stability control device is realized, and a decision basis is provided for scheduling operation personnel to adjust the configuration of stability control system control elements and adjust the operation mode.

The invention provides a wind farm power coordinative control method and system. The wind farm power coordinative control method is characterized in that the method includes steps: determining a reactive control work mode of a wind farm according to a power dispatching instruction; calculating a reactive loss of the wind farm; calculating a total reactive demand of the wind farm according to the reactive control work mode of the wind farm and the reactive loss of the wind farm; and distributing the total reactive demand of the wind farm according to a preset total reactive demand distributionrule of the wind farm, determining whether the total reactive demand of the wind farm exceeds a reactive output limit of a wind turbine generator system, bearing all the total reactive demand of the wind farm by the wind turbine generator system if not, and bearing the total reactive demand firstly by the wind turbine generator system and an excess portion by a reactive compensation device if yes.According to the technical method, the power grid friendliness of the wind farm is improved, the safe and stable operation level of the power grid of wind power massive centralized access regions isimproved, and the improvement of the wind power consumption capability of the power grid is promoted.

The invention discloses a quick response method for accident information of a power dispatching control center, and the method comprises the steps: enabling all substations to be connected to an intelligent power grid dispatching control system, and obtaining the point table information of all substations; carrying out optimization rectification on an original remote signaling signal in the pointtable information so as to reduce the total amount of monitoring information accessed to the system; configuring a delay alarm function for the intelligent power grid dispatching control system so asto filter short-time'action and reset 'signals under each fault condition; and monitoring personnel accurately and quickly determine fault information from the rectified and filtered fault informationpush graph, and reporting a fault tripping conclusion to a dispatcher in time after preliminary analysis and research and judgment. According to the quick response method for the accident informationof the power dispatching control center, the pressure of fault research and judgment under the accident condition of an on-duty monitor is greatly reduced, and the accident information processing time is shortened; and meanwhile, the pressure of monitoring personnel is reduced through monitoring information optimization, the monitoring efficiency is improved, and the safe and stable operation level of a power grid is improved.

The present invention provides a method and a system for avoiding same-tower multi-loop vertical connection zero sequence direction protection maloperation. The method and the system are based on station domain information, it is determined whether there is a loop with faults or not through determination of whether a first criterion is established, it is determined whether loops except the fault loops in the multiple loops with voltage levels having faults have zero sequence voltage zero-crossing points or not according to a second criterion, and when loops except the fault loops in the multiple loops with voltage levels having faults have zero sequence voltage zero-crossing points, the reverse compensation is performed; it is determined whether loops with voltage levels without faults have zero sequence voltage zero-crossing points or not according to a third criterion in a same-tower mixed voltage multiple loops, and if yes, the vertical connection zero sequence protection is closed.The method and the system completely solve the problems of the same-voltage and mixed voltage multi-loop vertical connection zero sequence direction protection maloperation of the same tower caused by open-phase operation or break line faults and ensure the precision of the vertical connection zero sequence direction protection so as to improve the electric system maloperation capacity and the power grid safe and stable operation level.