China Zhenglan Cable Technology Co., Ltd Company News

The metal shielding methods of medium-voltage XLPE insulated power cables are mainly composed of copper tape overlap wrapping shielding and sparse copper wire shielding. According to the GB/T12706-2008 standard for cables with rated voltage from 6kV to 35kV, the average overlap ratio of copper tape in the copper tape shielding method is not less than 15% of the width of the copper tape (nominal value), and the minimum value is not less than 5%. The thickness of copper tape for single-core cables is ≥ 0. 12mm, the average thickness of multi-core cables is ≥ 0. 10mm, and the minimum thickness of copper tape is not less than 90% of the nominal value. The copper wire shield consists of loosely wound soft copper wires, the surface of which should be fastened by reversely wound copper wires or copper tapes, and the average gap between adjacent copper wires should not be greater than 4mm. The shielding on the cable structure is a measure to improve the distribution of the electric field. The role of the metal shielding mainly has the following aspects: 1. When the cable is normally energized, the metal shielding layer passes the capacitive current, and when the short-circuit fault occurs, the short-circuit current passes. 2. The electromagnetic field caused when the cable is energized is shielded in the insulated core to reduce electromagnetic interference to the outside world, and the metal shielding layer also limits the impact of the external electromagnetic field on the interior. 3. The power station protection system requires the outer metal shield to have better lightning protection properties. 4. Homogenize the electric field to prevent axial discharge. Since the semi-conductive layer has a certain resistance, when the metal shielding layer is poorly grounded, the cable will discharge along the surface due to uneven potential distribution in the cable axis.

3. Wire and cable with aging insulation layer   The unqualified tensile strength and elongation of the insulating sheath before aging directly greatly shortens the working life of the wire and cable, and the insulator is easily broken during construction or in a long-term energized and high-temperature environment, resulting in live conductors. If exposed, there is a risk of short circuit that can cause electric shock. The main reasons for its failure are: first, the use of recycled materials for production to reduce product costs; second, small enterprises that do not have production qualifications cut corners for profit.

2. Wires and cables with unqualified structural dimensions The main problem of the structure size is the thickness of the sheath and the thickness of the insulation. When the sheath and insulation thickness of the cable do not meet the standard, the electrical strength of the wire and cable will be seriously reduced, resulting in a shortened service life of the wire and cable. and cables may break, insulation may not work properly, resulting in electrical shorts and fires.

On May 30, the country's first tidal-light complementary smart photovoltaic power station - National Energy Group Longyuan Zhejiang Wenling Chao-light complementary smart photovoltaic power station achieved full-capacity grid-connected power generation, creating a new energy comprehensive application of photovoltaic and tidal power generation in perfect harmony. This indicates that my country has made new achievements in the comprehensive utilization of marine energy and the three-dimensional development and construction of new energy.   The power station is the first and currently the only Chaoguang complementary smart photovoltaic power station in China. It is located in Wugen Town, Wenling City, Zhejiang Province. Silicon bifacial modules. The power station complements China's largest tidal power station, comprehensively utilizes solar energy and tidal energy, forming a scene of "the sun and the moon work together, and the water and the water generate power together".   It is understood that the level of intelligence and automation of the power station has reached the domestic first-class level, realizing few people and no one on duty. The power station uses UAV inspection technology and AI intelligent diagnosis system, relying on the big data analysis of the digital platform, to carry out remote diagnosis of photovoltaic power generation equipment health monitoring, to detect potential equipment problems in advance, and the early warning accuracy rate is over 85%, reaching the industry's leading position, achieving from The transformation from "people looking for information" to "information looking for people", equipment operation and maintenance has changed from passive to active, which effectively guarantees the economic benefits of the power station.

Dear All, Here comes China's traditional Dragon Boat Festival. We will be on holiday from Friday (June 3rd) to Sunday (June 5th). Work resume from June 6th(Monday). During holiday, we may have limited access to email, so shall any delays of response. Kindly ask for your understanding. Zhenglan Cable Technology Co., Ltd June 1st, 2022

Transmission process The transmission of electric energy, together with power transformation, distribution and consumption, constitutes the overall function of the power system. Through power transmission, the power plants far away (up to thousands of meters) are connected with load centers, so that the development and utilization of electric energy go beyond the regional limits. Transmission lines can be divided into overhead transmission lines and underground transmission lines according to their structural forms. The former consists of line towers, conductors and insulators, which are erected on the ground; The latter is mainly laid underground (or underwater) with cables. Transmission can be divided into DC transmission and AC transmission according to the nature of the transmitted current. This process uses different types or overhead bare conductors such as AAC, AAAC, ACSR, etc. Transformation process In the power system, the power plant converts the natural primary energy into electric energy and sends power to the remote power users. In order to reduce the power loss on the transmission line and the line impedance voltage drop, it is necessary to increase the voltage; In order to meet the security needs of power users, the voltage should be reduced and distributed to each user, which requires a substation that can increase and decrease the voltage and distribute power. Therefore, the substation is an electrical device in the power system that converts voltage, receives and distributes electric energy through it. It is an intermediate link between the power plant and power users. At the same time, the power grid of various voltage levels is connected through the substation. The function of the substation is to transform voltage, transmit and distribute electric energy. The substation is composed of power transformer, power distribution device, secondary system and necessary auxiliary equipment. The transformer is the central equipment of the substation, which uses the principle of electromagnetic induction. This process uses different types of cables such as high voltage, medinum voltage and low voltage power cable, aerial bundled cable, electrical wires.