China Zhenglan Cable Technology Co., Ltd Company News

Analyze the reasons for the unqualified wires and cables for everyone：   Marking is the main way for wires and cables to identify the basic information of products. According to standard regulations, the main content of the mark is: product model, specification, standard number, factory name, place of origin, etc. within a certain mark interval. When the mark is unqualified, it will cause the construction personnel's identification error, and in serious cases, it may cause electrical accidents.

1. Select the cable cross-sectional area according to the long-term allowable current-carrying capacity 1.1 In order to ensure safety and the service life of the cable, the temperature of the cable after power-on should not exceed the specified long-term allowable working temperature. The temperature is 70 degrees for polyvinyl chloride insulated cables and 90 degrees for XLPE insulated cables. According to this principle , It's very simple to look up the table and choose the cable. 1.2 Examples: A certain factory has a transformer capacity of 2500KVa and uses 10KV power supply. If XLPE insulated cables are used to lay in the bridge, what is the cross-sectional area of ​​the cable? Step 1: Calculate the rated current 2500/10.5/1.732=137A Step 2: Check the cable selection manual to know YJV-8.7/10KV-3X25 current carrying capacity is 120A YJV-8.7/10KV-3X35 current carrying capacity is 140A Step 3: Choose YJV-8.7/10KV-3X35 with a cable carrying capacity greater than 137A, which can theoretically meet the requirements. Note: This method does not consider the requirements of dynamic stability and thermal stability. 2. Choose the cable cross-sectional area according to the economic current density Simply understand the economic current density. The cross-sectional area of ​​the cable affects the line investment and power loss. In order to save investment, it is hoped that the cable cross-sectional area should be smaller; in order to reduce the power loss, it is hoped that the cable cross-sectional area should be larger; based on the above considerations, determine a reasonable one The cross-sectional area of ​​the cable is called the economic cross-sectional area, and the corresponding current density is called the economic current density. 3. Select the cable cross-sectional area according to the voltage drop of the power grid When we use the first and second methods to select the cross-sectional area of ​​the cable, if the cable is very long, a certain voltage drop will occur during operation and startup, and the voltage on the device side will be below a certain range, which will cause the device to heat up. 4. Select the cross-sectional area of ​​the cable according to the thermal stability coefficient (that is, select the cross-sectional area of ​​the cable according to the short-circuit current) 4.1 When the 0.4KV cable is protected by an air switch, the general cable can meet the thermal stability requirements, so there is no need to verify it according to this method. 4.2 For cables above 6KV, after selecting the cross-sectional area of ​​the cable using the above method, you must verify whether it meets the thermal stability requirements according to the following formula. If it does not meet the requirements, choose a larger cross-sectional area. Formula: Smin=Id×√Ti/C Among them, Ti is the breaking time of the circuit breaker, which is 0.25S, C is the thermal stability coefficient of the cable, which is 80, and Id is the three-phase short-circuit current value of the system. For example: when the system short-circuit current is 18KA, how to choose the cable cross-sectional area. Smin=18000×√0.25/80=112.5 Conclusion: If the system short-circuit current reaches 18KA, even if the rated current of the equipment is smaller, the cable cross-sectional area should not be less than 120mm2.

Dear all, With the National Day holiday, the specific arrangements for our National Day holiday are hereby notified as follows: Holiday time: 7days in total from October 1st to October 7th, 2021. During holiday, we may have limited access to email so for any of the delay of response of your email, kindly ask for your understading. After holiday,we will respond it  as soon as possible once we resume work. Best wishes Zhenglan Cable Technology Co., Ltd

Dear all, Here comes the Mid-Autumn Day holiday. Wish all of us a happy holiday. Kindly note this year holiday starts from September 19th to 21st, 2021. During holiday, we may have limited access to email so for any of the delay of response of your email, kindly ask for your understading. After holiday, we will get back to you at our earliest time after work resume. Regards Zhenglan Cable Technology Co., Ltd

1. Copper core or aluminum core can be used for cables and wires, and copper core cables or wires should be used for civil buildings; Copper core cables or wires shall be used in the following places: 1) Flammable and explosive places; 2) Important public buildings and residential buildings; 3) Especially humid places and places with corrosion to aluminum; 4) Places where people gather more; 5) Important reference room, computer room and important warehouse; 6) Mobile equipment or places with severe vibration; 7) Other places with special regulations. 2 the insulation type of conductor shall be selected according to the laying mode and environmental conditions, and shall comply with the following provisions: 1) In general engineering, under indoor normal conditions, PVC insulated and PVC sheathed cables or PVC insulated wires can be selected; If possible, XLPE insulated power cables and wires can be selected; 2) The selection of power supply lines for fire fighting equipment shall comply with the provisions of section 13.10 of this specification; 3) For buildings with high fire protection requirements such as class I high-rise buildings and important public places, flame retardant low smoke halogen-free XLPE insulated power cables and wires or smoke-free halogen-free power cables and wires shall be adopted. 3. The insulated conductor shall meet the requirements of working voltage. The indoor laying of plastic insulated wire shall not be less than 0.45/0.75kv, and the power cable shall not be less than 0.6/lkv;

CopperFundamental analysis   Global excess liquidity has triggered large fluctuations in asset prices, and the superposition of the new crown pneumonia epidemic has led to a mismatch of supply and demand. Non-ferrous commodities such as copper and aluminum staged a rare bull market. From a macro perspective, the U.S. non-agricultural employment data is far below expectations, and the market expects the Fed to continue its dovish policy. Last week, the net fund holdings rebounded rapidly, and the copper trading sentiment in the international market heated up. From a fundamental point of view, TC still maintains a momentum of recovery, and the strike of Chilean copper mine workers has ended; from the demand side, the price difference of refined copper scrap is at a historical low level. When the price drops to a low level, scrap copper holders are reluctant to sell. The market shifted to refined copper consumption. However, with the advent of September and October, consumption has entered a seasonal peak season and new energy demand has long been positive for copper prices. Short-term long-term factors are intertwined, and Shanghai Copper fluctuates within the range.