39results about How to "Reduce load shedding" patented technology

The invention provides a power grid AC / DC cooperation control method after a direct current block fault. The method comprises steps that characteristic quantity of a power grid is extracted based on power grid operating data obtained by a (Wide Area Measurement System), and the power limit of an interconnection tie of the regional power grid during static and stable operating is calculated; the overshoot of the power fluctuation peak value of the interconnection tie is calculated according to disturbance information which happens to the regional power grid; a load shedding quantification control measure needing to be taken is calculated based on the interconnection tie power peak value fluctuating theory and the unbalanced power redistribution theory. The method provided by the invention utilizes direct current power emergency control, so that coordination and cooperation of control measures between a large capacity direct current receiving end Central China power grid ultrahigh voltage alternating current system and a direct current system, thereby replacing or reducing the load shedding quantity of the Central China power grid, effectively improving the safety and operation efficiency of the power grid, and alleviating pressure that the imbalance impact power of the power grid is wide in influence range, the load shedding quantity is large and the like.

An Automatic load-reducing control method for integrating the voltage frequency dynamic mutual influence measures the state quantity information on site such as voltage, frequency and power so as to determine whether to act for implementing the load-reducing. The invention effectively takes account of the coupling degree of the voltage amount and the frequency amount under the corresponding operating condition by calculating the average frequency voltage correlation coefficient at the device installation nodes under a certain operating condition; calculating the synthetic state quantity in real time by measuring the voltage, frequency and active power of the installation node of each automatic load-reducing control device in real time and starting the automatic load-reducing control device in time based on the change circumstance, and acting in turn. The invention introduces the active power measurement into the traditional automatic load-reducing device, takes account of the interaction of the voltage and the frequency generated by the load active power and solves the problem that the device may not act or act excessively only based on the change of the frequency amount or the voltage amount.

The invention discloses a power system active scheduling method and system for coping with ice disasters, and the method comprises the steps: firstly quantifying the impact on the fault probability ofan element from the ice disasters, then abstracting the topological state transition of a system into a Markov chain during the ice disasters, and completing the analysis of the impact on a power system from the ice disasters through a network rasterized system model; establishing an active scheduling model based on a semi-Markov decision process, considering a recovery process of an element, andscheduling the power flow of the system again in advance. The power system active scheduling strategy model for the ice disasters can calculate the influence degree of disasters on the electric powersystem from two aspects of time dimension and space dimension, reduce threats brought by disasters from the active scheduling level, and has good perspectivity and load reduction reduction reductionreduction effects.

The invention discloses a method with a reactive power compensation fast switching function. The method mainly comprises a step of monitoring the bus voltage of a controllable capacitor in real time by using a safety automatic device and judging whether the system has a short circuit fault condition according to the monitoring of an actual voltage value of a busbar, a step of cutting off all the reactors on the same busbar or parallel busbar as a main transformer and then selecting to switch to a part of capacitors that can be switched under the main transformer, and a step of withdrawing a set of capacitors after a certain delay if over high voltage after system recovery is caused after switching to the capacitor, if overvoltage start still does not return, withdrawing a group of capacitors at regular intervals until all main transformer overvoltage on the same busbar or parallel busbar of the main transformer return or switched-on capacitors are removed. According to the method, thedynamic reactive power support capability of a receiving end power grid can be strengthened, the voltage stability of the power grid is improved, and a requirement of quickly switching on the capacitors under the condition of protection or switch rejection is achieved.

The invention discloses a dynamic adjustment method for the structure of a regional power grid in allusion to main transformer overload, and belongs to the technical field of power system operation control. According to the method, the topological structure of the power grid is dynamically adjusted through line switching, and a condition of main transformer overload is solved or relieved through changing flow distribution of the power grid; and the load balancing degree and the short-circuit current and voltage level of the power grid are comprehensively considered for a feasible power grid structure adjustment scheme, the weight of each single index is determined, then superior and inferior sorting is performed on the feasible schemes according to the size of a comprehensive index, and an optimal adjustment scheme is determined. According to the dynamic adjustment method, a load shedding operation is not required to be performed, and the power supply reliability of the regional power grid is improved.

The invention discloses a reclosing and emergency control integrated optimization method for a power grid based on a DSR (Dynamic Security Region). The reclosing and emergency control integrated optimization method comprises the following steps: analyzing a reclosing time domain of a system by adopting a method of the DSR; combining emergency control quantitative analysis and an optimal time emergency control strategy of the DSR; integrally optimizing the reclosing and the emergency control. The invention provides an optimal reclosing time scheme with the DSR as the reference when permanent faults occur; according to the method, the impact of unsuccessful reclosing on the system stability can be effectively relieved, and a safety limit of the system is improved.

The present invention discloses a three-layer heat and power combined supply microgrid energy control method for reducing wind curtailment. According to the method, the economic operation of a microgrid is divided into three time scales, namely, a day-ahead dispatching layer, a short-term adjustment layer and a real-time control layer. In the day-ahead dispatching layer, a dispatching period is divided into a plurality of periods, and day-ahead dispatching is converted into a mixed integer linear optimization problem based on day-ahead prediction data. In the short-term adjustment layer, short-term adjustment is converted into a non-linear optimization problem according to the startup-shutdown plans of the day-ahead dispatching layer and short-term prediction data. In the real-time control layer, a local controller carries out local control through adopting a flexible droop control mode according to a received optimization result of the short-term adjustment layer and actually-measured data. The three-layer heat and power combined supply microgrid energy control method for reducing wind curtailment is applicable to the grid-connected economic operation of a heat and power combined supply microgrid comprising various controllable power sources, uncontrollable power sources, heat storage, energy storage batteries and controllable loads, and is especially suitable for a heat and power combined supply microgrid containing wind curtailment.

The invention provides a power distribution network stability analysis method in an electric power system; the topological structure of the network structure of a large-scale actual power distributionnetwork is simplified, and the simplified power distribution network structure is obtained, so that accurate analysis and calculation are facilitated; the stability initial parameters of the power distribution network after simplification are counted, and the stability initial parameters of the power distribution automation system are counted; the power failure information of the load point of the power distribution network is counted; the stability initial parameters and the power failure information are combined for carrying out fault influence analysis on the power distribution network elements by adopting a traversing method, and a load point outage information base is established; and the load point outage information base is combined, and power distribution network stability analysis and prediction are carried out, so that the comprehensive operation monitoring analysis capability of the power distribution network is remarkably improved.

The invention relates to a condensation method of halogenated butyl rubber, and belongs to the technical field of butyl rubber synthesis. The condensation method comprises the following steps: performing halogenation reaction on a glue solution of butyl rubber, performing neutralization reaction, introducing an obtained product into a first condensation kettle, introducing hot water into the firstcondensation kettle, generating a first gas phase containing hexane in the first condensation kettle, condensing the first gas phase through a condenser, and introducing the condensed first gas phaseinto a hexane purification system for treatment; pumping colloidal particle water in the first condensation kettle into a second condensation kettle by using a first conveying pump, and generating asecond gas phase containing hexane in the second condensation kettle, and extracting the second gas phase from the second condensation kettle by using a first water ring vacuum pump and introducing the second gas phase into the hexane purification system to be treated after being condensed through a condenser. The steam waste heat at the top of the first condensation kettle is recycled by adoptinga mechanical heat pump, so that the steam consumption in the halogenated butyl production process is reduced, and the use amount of circulating water consumed by condensed steam is also reduced.

The invention provides an integrated evaluation method for a distribution system. The method comprises (1), an electric parameter, an element reliability parameter, and an initial network topological structure of a distribution system are obtained and a system reliability evaluation model is established; (2), a non-normal operation state of the distribution system is selected, reactive power compensation and optimization are carried out to realize correction and improvement, and then power supply reliability is evaluated; (3), a system state is generated, a non-normal state different from the previously listed non-normal state of the system is selected and the step (2) is repeated until a convergence condition is met; and (4), a reliability index and an overall power quality index of the whole distribution system are calculated and outputted. According to the method, reliability evaluation of the distribution system and system state correction are combined and correction on the non-abnormal operation state of the system is added, so that the voltage and wire losses are improved and the switching load in a non-abnormal state of the system is reduced. Therefore, indexes of the overall reliability and power quality of the system are improved correspondingly; and the integrated operation monitoring evaluation capability of the distribution network is enhanced obviously.

The invention discloses a coordinated control method for improving the frequency stability of the power grid after DC blocking. The cooperative control master station receives the DC blocking information sent by the DC control execution station, and obtains the control amount and the effective control object set from the matching of the control strategy table; The control master station identifies the current effective control quantities of DC, energy storage, and load controllable objects, forms real-time control measures, and sends them to the DC control execution station, energy storage control execution station, and load control execution station to coordinate and complete emergency control. The invention provides a coordinated control method for improving the frequency stability of the power grid after DC blocking, which can be used to solve the priority order problem of various control objects after the DC blocking of the receiving power grid, and is beneficial to make full use of the available DC, energy storage, and load systems. control characteristics, improve the frequency stability of the system, avoid reducing load shedding, and improve the economy and safety of power system operation.

The invention provides a multi-scheme comprehensive evaluation method for the automatic low-frequency load reduction of a large electric network, which realizes that the design of a plurality of schemes of low-frequency load reduction, the comprehensive evaluation and comparison and the mass simulated checking and calculation of a recommended scheme are all finished automatically by a program, realizes an integrative procedure, changes a traditional calculation mode that engineering staff carries out manual calculation, and enhances the efficiency and the accuracy of the establishment of the automatic low-frequency load reduction schemes greatly. The method has rationality, applicability and generalizability.

A power conversion method and system for a DC power transmission system are provided. The method comprises when a hybrid DC power transmission system in an asymmetric topology operating condition hasan operating condition in which a converter station valve group is out of operation, calculating the power of each valve group before the converter station valve group is out of operation based on atotal power value of the current converter station; and resetting the power reference value of the converter station based on the power of each valve group before the out of operation of the valve group and the number of the out-of-operation valve groups. The method and system improve the flexibility of system operation, minimize system power loss, reduces grid frequency changes, reduces generator tripping and load tripping.

The invention relates to a coagulation method of halogenated butyl rubber, which belongs to the technical field of butyl rubber synthesis. After the butyl rubber glue has undergone a halogenation reaction, and then undergoes a neutralization reaction, it enters the first coagulation kettle, and hot water is also passed into the first coagulation kettle, so that the first gas phase containing hexane is generated in the first coagulation kettle. The first gas phase is condensed by the condenser and then enters the hexane purification system for treatment; the colloidal water in the first coagulation tank is sent to the second coagulation tank through the first delivery pump, so that the second gas phase containing hexane is produced in the second coagulation tank, The second gas phase is extracted from the second condensation tank by the first water ring vacuum pump, condensed by the condenser, and then enters the hexane purification system for treatment. Using a mechanical heat pump to recycle the steam waste heat at the top of the first condensation tank will not only reduce the steam consumption in the production process of halogenated butyl, but also reduce the amount of circulating water used for condensing steam.

The invention relates to a power system intelligent low-frequency low-voltage load reduction method based on an intelligent household electrical appliance. The method comprises the following steps: when large disturbance in a system is monitored, determining whether the frequency and the voltages of the system are decreased to preset load reduction motion values, and once the frequency and the voltages reach the load reduction motion values, obtaining power shortage in the system and determining a load capacity which should be cut from the system; starting an intelligent household electrical appliance load reduction module; starting low-frequency low-voltage load reduction; and if intelligent household electrical appliance load reduction cannot enable the system frequency and voltages to restore to normal operation scopes and the frequency and voltages are continuously decreased to preset values of the low-frequency low-voltage load reduction, starting the low-frequency low-voltage load reduction, according to a residual load reduction amount, successively starting a basic round and a special round of low-frequency load reduction for cutting off loads until the frequency is restored to the normal operation scope, and embedding one low-voltage load reduction module in each round of low-frequency load cutting. According to the invention, after a power system is disturbed, the frequency and voltages can be effectively and rapidly inhibited from dropping and even collapsing, the load cutting amount is small, and the economic loss is small.

The present invention discloses a three-layer heat and power combined supply microgrid energy control method for reducing wind curtailment. According to the method, the economic operation of a microgrid is divided into three time scales, namely, a day-ahead dispatching layer, a short-term adjustment layer and a real-time control layer. In the day-ahead dispatching layer, a dispatching period is divided into a plurality of periods, and day-ahead dispatching is converted into a mixed integer linear optimization problem based on day-ahead prediction data. In the short-term adjustment layer, short-term adjustment is converted into a non-linear optimization problem according to the startup-shutdown plans of the day-ahead dispatching layer and short-term prediction data. In the real-time control layer, a local controller carries out local control through adopting a flexible droop control mode according to a received optimization result of the short-term adjustment layer and actually-measured data. The three-layer heat and power combined supply microgrid energy control method for reducing wind curtailment is applicable to the grid-connected economic operation of a heat and power combined supply microgrid comprising various controllable power sources, uncontrollable power sources, heat storage, energy storage batteries and controllable loads, and is especially suitable for a heat and power combined supply microgrid containing wind curtailment.

The present invention relates to the field of power grid dispatching control, in particular to a regional power grid optimal load control method considering regional balance, which is characterized in that it includes the following steps: A) obtaining the total amount of load control; B) calculating the target amount of load removal in each area; C) Select the line to be pulled from the pull-limit sequence table; D) Construct the full load shedding model and the short load shedding model; E) Build the regional load balance model; F) Calculate the full load cut off and short load in each area Cut-off and regional load balance value; G) Output the cut-off lines in each region; the region refers to the county-level power supply units and district-level power supply units within the jurisdiction of the regional power grid. The beneficial effects of the present invention are: on the basis of satisfying the shedding load, the total shedding load can be reduced, excessive shedding can be avoided, economy and regional fairness can be effectively taken into account, the load shedding can be reduced to the greatest extent, and the power grid can be fully guaranteed Scheduling fairness.

An Automatic load-reducing control method for integrating the voltage frequency dynamic mutual influence measures the state quantity information on site such as voltage, frequency and power so as to determine whether to act for implementing the load-reducing. The invention effectively takes account of the coupling degree of the voltage amount and the frequency amount under the corresponding operating condition by calculating the average frequency voltage correlation coefficient at the device installation nodes under a certain operating condition; calculating the synthetic state quantity in real time by measuring the voltage, frequency and active power of the installation node of each automatic load-reducing control device in real time and starting the automatic load-reducing control devicein time based on the change circumstance, and acting in turn. The invention introduces the active power measurement into the traditional automatic load-reducing device, takes account of the interaction of the voltage and the frequency generated by the load active power and solves the problem that the device may not act or act excessively only based on the change of the frequency amount or the voltage amount.

Provided is a power distribution network single-phase earth fault network reconstruction method. The power distribution network single-phase earth fault network reconstruction method comprises the following steps: after earth fault, all power restoration zones are divided into two groups, branch circuits locating in the same section bus with fault circuits are divided into a group A, and power restoration circuits locating in different section buses are divided into a group B; for all power restoration circuits of the two groups, on the premise of voltage meeting constraint conditions, a power restoration circuit with a smallest network loss value in the group A is preferentially selected to avoid power failure in the power restoration process, a hot switch operation is conducted at the moment, namely, bus interconnection switches are closed, and then circuit breakers in failure positions are tripped off. For power restoration circuits of the group B, a cold switch operation is conducted, namely, the circuit breakers in the failure positions are tripped off, and then the bus interconnection switches are closed. The power distribution network single-phase earth fault network reconstruction method preferentially selects the hot switch operation which fully uses characteristics of single-phase earth faults, so that a power distribution network can operate in a normal condition or with faults. Besides, the power distribution network single-phase earth fault network reconstruction method ensures power supply quality of users, improves reliability of power supply, and has high operability and superiority. The power distribution network single-phase earth fault network reconstruction method is mature in technology and high in reliability.

The invention discloses a method and a system for evaluating restoration capacity and reliability of a power distribution network. The method comprises the steps of: establishing a power distribution system element reliability model, and determining the influence type of each element fault on each load in the power distribution system element reliability model through employing a minimum path method; establishing a fault influence table, performing power distribution system operation simulation by using a Monte Carlo method, and when a fault occurs, reconstructing a power distribution system network; and querying a corresponding influence type in the fault influence table, counting power failure times and power failure duration, and calculating a reliability index according to the power failure times and the power failure duration to realize reliability evaluation. By means of the method, more loads can be restored, the load shedding amount is reduced, the restoration capacity of the system after disasters is improved, and the elasticity of the power system is improved.

The present invention belongs to a method for optionally cutting off a fault point of double branch circuits at the low voltage side of a transformer, which comprises the following steps of: (1) when earthed fault occurs, measuring instantaneous values of current I0 of an earthed neutral point and an triphase current of each branch at the low voltage side of the transformer; (2) calculating amplitude values of the I0 and zero-sequence current I01 and I02 of two branches at the lower voltage side of the transformer; (3) automatically analyzing the relation between the amplitude values of I0, I01 and I02; and (4) according to an analyzing result of the step (3), enabling a corresponding circuit breaker to actuate by sections and time delay to complete the cutoff of the failed branch. The method carries out discrimination by utilizing the distribution feature of zero-sequence fault current flowing through two branches at the low voltage side of the transformer when low-resistance earthed fault occurs and intelligently identifies the faulted branch circuit at the low voltage side of the transformer; and compared with the prior protection proposal, the method effectively shortens the load cutting range, improves the reliability of power supply for a user, reduces the blackout range caused when the earthed fault is earthed and changed into zero-sequence protecting action and protects the power load as large as possible.