State Grid Corporation of China

Taizhou Power Supply Company of State Grid Zhejiang Electric Power

Zhejiang Sci-tech University

China National Silk Museum

Hao Li

Zhen Huang

Jian Wu

Guode Ying

Tao Zhu

Kang Wang

Yuande Zheng

Hua Xu

Hao Tan

Ping Zhao

Zaibing Zhou

Xiaochun Xu

Qingchun Zhao

Xiaotong Zhu

Yiping Shen

Yutao Qiu

Ben Li

Yong Liu

Chi Zhang

Yang Zhou

Chen Zhou

Xu Jiang

Zheng Qin

Dan Yang

Rui Jia

Bing Wang

Zhiqin Peng

Hailing Zheng

Rijun Wang

Hailiang Yang

Liling Jia

A purification method for detection of a strontium isotope in a silk cultural relic. The method includes: (1) enrichment of the strontium isotope: after cleaning the silk cultural relic, adding the silk cultural relic to a digestion agent for microwave digestion, and conducting evaporation drying; and adding a dried product to a nitric acid solution for centrifugal separation, and extracting a supernatant; and (2) purification of the strontium isotope: first, mixing 4',4″(5″)-di-tert-butyldicyclohexano-18-crown-6 and a defoamer and adsorbed to a purified resin separation column, and pre-cleaning the purified resin separation column with a nitric acid solution; next, injecting the supernatant in step (1) into the purified resin separation column with a nitric acid solution as a carrier solution; and then, injecting anSr solution and an elution solution into the purified resin separation column in sequence to obtain a separated and purified strontium solution.

Purification method for detection of strontium isotope in silk cultural relic

Provided is a determination method of differential protection suitable for an electricity transmission line with multi-terminal T-connection. The determination method includes: sampling and calculating all phase currents, and calculating a maximum fault component current &#x394;&#x130;in phase current amplitudes of each phase current, a differential current Iin the each phase current, a resistive current Iin the each phase current and a vector sum &#x394;&#x130;of fault component currents except &#x394;&#x130;in the phase current amplitudes of the each phase current; and comparing the maximum fault component current &#x394;&#x130;in phase current amplitudes of each phase current and a threshold setting value I, determining a value of a resistive coefficient K corresponding to the phase current amplitudes of the each phase current according to a comparison result, and performing differential determination on the differential current Iand the resistive current Iin phase current amplitudes of the each phase current according to a differential determination formula: if the differential current Iof the target phase satisfies the above differential determination formula, it is determined that a fault occurs in an area of the target phase.

Differential protection determination method

Provided are a differential protection method and system, applied to a multi-terminal T-connection transmission line. The method includes: selecting two slaves without a connection and connecting the two slaves to construct a slave group; determining a target slave and an auxiliary slave in the slave group, where a first communication path is connected along a channel one, a channel two and a channel three, and a second communication path is connected along the channel three, the channel two and the channel one; transmitting, by the target slave, two frames of messages, and acquiring a delay difference between a transceiving delay of the first communication path and a transceiving delay of the second communication path, where a first frame of messages is transmitted to the target slave via the first communication path, a second frame of messages is transmitted to the target slave via the second communication path.

Differential protection method and system

Growing community of inventors

Zhejiang, China

Hao Li