9results about How to "Improve quickness" patented technology

A low-frequency system fault judgment method and relay protection device based on electrical quantity calculation discretizes continuous electrical quantity signals into digital quantity sampling values ​​through a fixed sampling frequency, and then uses the current sampling value and the historical sampling value to calculate the effective value of the electrical quantity through the sampling value product algorithm. According to the instantaneous value of the electrical quantity and the effective value characteristics compared with the set action threshold, it can act quickly when the system fails. On the basis of ensuring reliability, the present invention can greatly improve the speed of low-frequency system relay protection, and avoid the expansion of the fault range or equipment damage caused by too slow protection action.

The application discloses a kind of multi-objective sled dog protection optimization method and system based on myxomycete dynamic weight, it is related to power distribution network relay protection technical field, including: obtaining fault current to establish action response characteristic model and sensitivity index, construct anti-time limit overcurrent protection double-objective optimization function;Global optimization is carried out using improved multi-objective sled dog algorithm, population is initialized by Piecewise chaotic mapping, dynamic weight is adaptively distributed by introducing myxomycete algorithm in local search stage, and individual position is updated in combination with local difference disturbance strategy;The solution set is objectively and comprehensively evaluated using entropy weight TOPSIS strategy and the optimal compromise setting value is output.The optimization method effectively resolves the conflict that traditional protection is difficult to consider both speed and sensitivity, and effectively guarantees the safe and reliable operation of the distribution network with distributed power supply.

The invention relates to a direct current transmission line single-ended traveling wave protection method based on a fault voltage first traveling wave area ratio. The method comprises the following steps: S1, determining an internal and external fault identification criterion of a forward region; s2, establishing a protection starting criterion; s3, establishing a fault direction criterion; s4, establishing a fault pole selection criterion; and S5, determining a protection scheme. According to the method, internal and external faults can be identified and accurately distinguished within 1ms, high sensitivity and reliability are still achieved under the high-resistance fault condition, and meanwhile good robustness is achieved under noise interference and parameter change of the current limiting reactor.

This invention discloses a dual-channel spraying device for weed control during crop seedling stages, belonging to the field of agricultural pesticide application technology. It includes a frame and a spray boom mounted on the frame. The spray boom is equipped with a lifting mechanism to raise and lower the boom and maintain its stability. A foldable spray boom is mounted on the boom. Below the spray boom are a target nozzle array and a sealing nozzle array. The target nozzle array is used for targeted spraying of seedling weeds, while the sealing nozzle array is used for sealing spraying of the soil surface in the work zone. The target nozzles of this invention employ a small cone angle and close spacing, enabling precise, point-to-point spraying of weeds and avoiding the waste of pesticide and the risk of crop damage caused by uniform spraying across the entire area. The sealing nozzles employ a large fan angle and wider spacing, forming a continuous and uniform pesticide film through droplet overlap, ensuring consistent sealing effect. The two spraying modes complement each other on the same platform, balancing precision and comprehensiveness.

The invention relates to the technical field of pesticides, in particular to a pyriproxyfen-buprofezin dispersible oil suspending agent and a preparation method thereof.The pyriproxyfen-buprofezin dispersible oil suspending agent is prepared from, by weight, 3-10 parts of pyriproxyfen active compound, 10-20 parts of buprofezin active compound, 2-10 parts of nonionic-anionic compound emulsifier, 2-10 parts of dispersing agent, 0.1-2 parts of stabilizer and 20-50 parts of dispersion medium, by compounding pyriproxyfen and buprofezin according to the mass ratio of 1: (2-4), especially compounding according to the mass ratio of 1: 3, under the matching action of other auxiliaries in a system, the insecticidal composition has a good control effect on pests on fruit trees, vegetables, grain crops, fiber crops and legume crops, and especially has the fast-acting property and the persistent effect of controlling tomato bemisia tabaci obviously higher than those of a single-component preparation.

A traction network three-terminal differential protection system applied to group cut-through power supply is composed of intelligent units installed in electrified railway traction substations, parallel stations and subareas, traction network differential protection devices and traction network differential protection channels between the substations, and a downlink line and an uplink line of an electrified railway are each provided with a three-terminal differential protection system. The traction network differential protection channel is composed of optical fiber channels among substations, parallel stations and subareas of an electrified railway, and the traction network three-terminal differential protection device is used for receiving digital voltage, current and switching value signals sent by the intelligent units of the substations. According to the invention, when the traction network fails in a group through power supply mode, the fault power supply unit is accurately positioned and the fault is rapidly removed, the differential current of the same row in the power supply unit is adopted to distinguish the fault from the load, the sensitivity, selectivity and quickness of traction network protection are effectively improved, the protection range is large, the selectivity is good, and the reliability is high. And the reliable operation of the power supply system is supported.

The present application belongs to the technical field of electrified railway traction power supply, and particularly relates to a traction network multi-terminal longitudinal differential protection system and method under a double-sided through AT power supply mode. The system sets multi-terminal longitudinal differential protection elements according to uplink and downlink feeders, covers multi-terminal branches composed of traction substations, AT substations and partition substations, and each branch is configured with a current transformer. The protection element includes a power frequency variation current differential element, a T-line / F-line current differential element and a low-voltage differential current starting element, which are respectively adapted to fault transient and steady state characteristics, and realize rapid fault identification and accurate removal through cooperative action. The method combines current threshold criterion, voltage criterion and opposite side allowable signal to ensure the rapidity, selectivity, sensitivity and reliability of action, realize rapid removal of fault two-end power supply, reduce the fault isolation range, and ensure the safe and stable operation of the traction network.

The present invention discloses an offshore double-fed wind turbine and supporting boost equipment electrical protection device and method, including a first current transformer, a second current transformer, an incomplete differential protection device and a first circuit breaker, wherein the first current transformer is installed on the high-voltage side line of the boost transformer, the second current transformer is installed on the stator current output line of the wind turbine, the incomplete differential protection device is electrically connected to the first current transformer and the second current transformer respectively, the high-voltage side current I1 of the boost transformer and the stator current I2 of the wind turbine are taken as input signals, the first circuit breaker is installed on the ring network cabinet line and electrically connected to the incomplete differential protection device to realize circuit breaking protection. The present invention significantly improves the sensitivity, reliability, selectivity and speed of protection of equipment such as offshore wind turbines, frequency converters, boost transformers and their connecting cables, and is not affected by the low voltage ride-through working conditions of the wind turbine, effectively reducing the probability of electrical damage to the equipment.

The invention discloses a zero-sequence inverse time limit overcurrent protection optimization method and system for a power transmission line, and the method comprises the steps: collecting and calculating the zero-sequence voltage and zero-sequence current of a local side and an opposite side of the line, and reversely deducing the zero-sequence voltage of the opposite side in combination with the zero-sequence impedance of the line. Zero-sequence inverse-time-limit acceleration is realized when a backstepping and actually-measured opposite-side zero-sequence voltage difference is relatively large, and acceleration is not performed when backstepping and actually-measured opposite-side zero-sequence voltages are consistent. And in zero-sequence inverse time limit acceleration, the maximum branch coefficients of other branches outside the fault line are considered to improve the acceleration speed. And after the zero-sequence inverse time limit is subjected to acceleration triggering, the minimum action time in zero-sequence inverse time limit logic is shortened, and meanwhile, the zero-sequence inverse time limit calculation time and the matching time are changed into OR, so that override action caused by relatively large zero-sequence current of other branches is avoided. According to the invention, the action speed of zero-sequence inverse time-lag protection during grounding and disconnection faults in the area can be accelerated, the self selectivity is improved, other branches are prevented from surpassing maloperation, and the action performance of zero-sequence inverse time-lag protection is improved.