Knowledge of power cord

The components of a power cord are as follows:
1. Copper wire. Copper wire is the core part of power cord. Copper wire is the carrier of current and voltage. The quality of a power cord depends on three points, namely, the density of copper wire, the material of the cord, the amount of copper wire, and the flexibility.
2. Inner sheath. Inner sheath is the material wrapped between the shielding layer and the wire core, also known as insulation sheath. The materials used are generally polyvinyl chloride plastic, polyethylene plastic or low smoke halogen-free. To ensure the safety of our power supply and prevent any leakage between copper wire and air.
3. Outer sheath. Outer sheath is the outermost protective layer (sheath) of the power cord, which plays the role of protecting the power cord. It is characterized by temperature resistance, cold resistance, oil resistance, water resistance, natural light interference, good winding performance, environmental protection, long service life.
Classification of power cord:

Power lines can be classified according to safety certification, the shape of the power cord plug and the standard of electricity consumption in different areas.
1. According to safety regulations, there are UL, CCC, VDE, PSE, SAA, UC, IRAM, IMQ, BSI, KS, PSB, SABS and so on.
2. According to the shape of the power cord plug, it can be divided into two flat power cord, three power cord, two round power cord, straight power cord, bent power cord, etc.
3. According to the standard can be divided into different parts of the electricity, the standard power cord, China standard power cord, European standard power cord, Japan standard power cord, the Australian standard power cord, the Brazilian standard power cord, Argentina standard power cord, power cord, Italy, the British standard power cord, South Korea standard power cord, standard power cord in Singapore, South Africa’s standard power cords, etc.

Manufacturing process:
Copper and aluminum single wire drawing of power cord – single wire annealing of power cord – stranded conductor of power cord – insulation extrusion of power cord – wire forming – Inner sheath of power cord – wire armor – outer sheath of power cord
Tips for identifying:
The identification method of power cord namely five look: look the quality qualification certificate of home appliance; Check the cross section of the wire; Look at the appearance of the power cord; Look at the core of the power cord; Look at the length of the power cord.
Above is a few small knowledge of power cord, hope to be helpful to everybody.

How to prevent wire and cable damage?

Wires and cables are easily affected by the external use environment. Careless protection will easily lead to hardening of the wire body, peeling off of insulation skin and other phenomena. Many users will mistakenly believe that the product quality has problems, which in fact has a great relationship with the temperature. The outer skin of electric power cable and wire products is mostly ordinary plastic or rubber. When the environment is below zero, the wire body of the whole electric wire and cable products will become hard and brittle, which may lead to the peeling and damage of the outer skin under the action of slight external forces. Cables may be damaged if not properly transported.

So, how to prevent damage to power lines and cables? You are advised to take the following precautions:
I. Pay attention to protective measures during ex-factory transportation: Protective measures are required when products are ex-factory loaded onto the means of transport. Such as the use of closed means of transport, to prevent direct exposure of the product; A soft cushion, such as a bedclothes or other soft foam, applied to a product; Handle with care when loading, do not load roughly, and avoid excessive bending.
2. Pay attention to prevent mechanical damage when unloading: When arriving at the destination or the construction site, the product supplier had better dispatch personnel to supervise and prevent the product from causing mechanical damage due to rough operation behavior during unloading.
3. Indoor storage and laying isolation layer: It is better to store the products indoors, and at the same time lay an isolation layer on the stored ground, such as wood boards, bedding, foam, etc., to prevent the products from being exposed to cold and moisture. Pay attention to prevent the products from being scratched by the wires and cables in direct contact with the ground.
4. Pay attention to control the temperature and prevent scratch during installation of the product: it is better to choose to work under the condition of warm temperature in mid-afternoon. If possible, you can warm up the product in advance with the heater and other equipment before use, so that the product can achieve the best performance. If it is buried, can be laid in the cable trench with a protective layer, such as cloth, foam, etc. If you are wearing a tube, make sure the inside and outside of the tube is smooth in advance, so as not to scratch the wire. Iron pipe should pay special attention to the purchase of qualified iron pipe, low quality iron pipe tube may have a lot of sharp raised points, it is very likely to scratch the cable skin.

High temperature resistant wire and cable

Resistance to high temperature wire and cable is suitable for the communication additional voltage up to and including 0.6/1 kv for fixed installation, power transmission and distribution line motor lead wire, high temperature resistance, corrosion resistance, resistance to acid and alkali and corrosive gas, waterproof properties, such as high temperature environment safe electrical function, large carrying capacity, long using life, widely used in metallurgy, electric power, petrochemical, building, large car production.

One: FF, FFP, FF22, FFP22, FV22 KGG silicone rubber insulated and sheathed control cable KGGR soft silicone rubber insulated and sheathed control cable has good thermal stability, can stick to in high temperature, low temperature, corrosive outstanding electrical function and softness, metallurgy, electric power, petrochemical and other appropriate professional use which have special requirements such as mobile and heat-resistant occasions.
Two:Commodity Performance Specification Q/HHTZH004.2 Flame retardant and fire resistance test Performance GB12666-90 specification
Three: Use characteristics
Communication extra voltage: U0/U 450/750kV
High temperature wire and cable is a cable that can normally transmit signals or electrical energy at high temperature. Flame-retardant cable refers to the cable in which the sample is burned under the specified test conditions, and the flame spread only within a limited range after the removal of the test flame source, and the flame or flame can go out by itself within a limited time. The fundamental feature is that in the event of a fire it may burn out and not be operational, but it prevents the fire from spreading. Colloquially, in the event of a fire, the power line can limit the combustion within a local scope, do not produce spread, keep other various equipment, avoid causing greater losses.

(1) In order to reduce fire accidents caused by heating and burning of cables in metro, power stations, office buildings and public places, current flame retardant cables are mainly halogen flame retardant. In case of fire, a lot of smoke will be generated and toxic, irritating and corrosive hydrogen halide gas will be generated; Smoke can hinder fire fighting and evacuation, and hydrogen halide can corrode equipment and endanger human health.
(2) Petrochemical, steel, aerospace, shipbuilding, military industry, pharmaceutical, food, plastic machinery, boiler and other industries related to heat and high temperature need to be able to withstand a certain high temperature wire and cable
(3) Fire-resistant cables are used in high-rise buildings, subways, power stations and some important places, etc., with fire protection characteristics of environmental occasions. In addition to transmitting power under the rated working voltage of 0.6/1kV, it can also operate safely for a certain period of time in the case of combustion, and for 3 hours in the case of flame burning at a high temperature of 950-1000 degrees Celsius. This greatly improves the safety factor of fire-resistant cables, which has won a certain amount of time for fire rescue.

Single-conductor cable and dual-conductor cable

Cable is made of cable structure, with power as the energy, the use of alloy resistance wire or carbon fiber heating far infrared for electrification and heating, known as carbon fiber floor heating, to achieve the effect of heating or insulation. There are usually single and double conductors, known as heating cables.
The difference between single guide cable and double guide cable
The heating cable can be divided into single conductor and double conductor. There are some differences between them in structure and performance.

Because of the structural characteristics of double guide cable, it is more convenient to install than single guide cable in the construction process. Both ends of the single guide cable need to be connected to the power supply, so the cable tail should be pulled back to the limit when laying. This requirement is difficult to operate under multiple conditions, such as large room area and long cable. Small room area and limited laying area; Room structure is complex, the side wall is not straight line but by a lot of broken lines. Dual guide cables do not need to consider these issues. Since the cable itself is a loop, all wiring is at the same end. In the construction, as long as the wiring terminal connects the power supply without considering the end of the cable, it can be laid at will according to the specific situation, which expands the practicability of cable ground laying.
The difference between double guide cable and single guide cable is obviously that the electromagnetic radiation double guide cable is much smaller than the single guide cable. Why does a single conductor cable have electromagnetic radiation and a double conductor cable does not? This is determined by their internal structure, from the physics can know, the conductor current is the magnetic field, the direction of the magnetic field is determined by the ampere rule. Ampere’s rule: In the case of a straight current, extend your right hand and hold the wire (the wire). The direction indicated by your thumb is the direction of the current, and the direction indicated by your bending four fingers is the direction of the magnetic field induced by the current passing through.
The structure of two kinds of heating cables determines that the failure rate of them is very different. In general, the failure rate of single guide can reach 35%, while the failure rate of double guide is much less than 0.1%, almost without any failure.

Quality inspection index of wire and cable

The inspection of wire and cable has always been an important part of national standard wire and cable. The higher the quality inspection department of a wire and cable enterprise is, the better the quality of the wire and cable produced by the enterprise is and the more trustworthy it is. And the more stringent the third-party quality inspection department is, the more conducive to the development of the industry.

1.Measurement of dc resistance of wire

The conductor cores of electric wires and cables mainly transmit electric energy or electrical signals. Conductor resistance is the main index, its electric performance of the ac voltage effect when the wire core resistance due to the surface of skin effect and proximity effect than dc voltage function, but when the electric frequency of 50 hz and small lines of standard specifies requirements that are only now the core of dc resistance or the resistivity is more than standard value, through the inspection can be found in the process of production of certain defects, such as broken wire or part of the single fracture; Traverse section does not meet the standard; Incorrect length of product, etc.

2. Test insulation resistance

The insulation resistance is an important index to reflect the insulation characteristics of wire and cable products, which is closely related to the electrical resistance, dielectric loss, and the gradual deterioration of insulation materials in the working state. For communication cables, if the insulation resistance between wires is too low, it will also increase circuit attenuation, cross-talk between circuits and long-distance power supply leakage on the conducting wire core, etc., so the insulation resistance shall be higher than the specified value.

3. Measurement of capacitance and loss factor

When the cable is applied with an AC voltage, a current flows through it. When the amplitude and frequency of the voltage are constant, the capacitive current is proportional to the capacitance of the cable (Cx). For ultra high voltage cables, the current of the capacitance may be comparable to the rated current, which becomes an important factor limiting the cable capacity and transmission distance. Therefore, the capacitance of the cable is also one of the main electrical performance parameters. By measuring the capacitance and the loss factor, it can be found that the insulation is affected by moisture, the insulation layer and the shielding layer fall off and other kinds of insulation deterioration phenomenon. Therefore, the measurement of capacitance and TAN delta is always carried out in the cable manufacture or operation.

4. Insulation strength test

The insulation strength of wire and cable refers to the ability of the insulation structure and material to withstand the action of electric field without breaking down. In order to check the quality of wire and cable products and ensure the safe operation of the products, all types of insulation wires and cables generally need to conduct insulation strength tests. The insulation strength test can be divided into pressure test and breakdown test. The voltage of time is generally higher than the rated working voltage of the test product. The specific voltage value and withstand voltage time are stipulated in the product standard. Through the withstand voltage test, the reliability of the product operation under the working voltage can be tested and serious defects in insulation can be found, as well as some shortcomings of the production process can be found

5. Aging and stability test

The aging test is a stability test that can maintain stable performance under the action of stress (mechanical, electrical, thermal). Thermal aging test: The simple thermal aging test is to test the characteristics of the test product under the action of heat aging. The test product is placed in an environment with a certain value above the rated working temperature, so as to obtain a shorter life at a higher temperature.

6. Thermal stability test

The thermal stability test is to evaluate the insulation stability by measuring some sensitive performance parameters after the cable is heated by current and subjected to a certain voltage during a certain period of heating. Insulation stability test can be divided into long-term stability test or short-term accelerated aging test.

Us gas capacity and demand and cables

The US energy Information Administration (EIA) said in its Short Term Energy Outlook (STEO) that the days of the us have been reduced by government measures to slow the spread of the coronavirus, reducing economic activity and energy prices.

Gas production and demand will fall from last year’s record highs in 2020 and 2021.
The EIA expects dry gas production to fall from a record high of 92.21 BCFD (BCF/d, the same below) in 2019 to 89.24 BCFD and 84.23 BCFD in 2021.

The EIA also expects gas consumption to decline from a record 84.97 BCFD in 2019 to 82.35 BCFD in 2020 and 78.62 BCFD in 2021.

This would be the first annual decline in consumption since 2017 and the second consecutive decline since 2006.

The EIA’s July 2020 gas supply forecast is lower than its June forecast of 89.65 BCFD and its latest 2020 demand outlook is higher than its June forecast of 81.87 BCFD.

It forecast US LNG exports to reach 5.35 BCFD in 2020 and 7.28 BCFD in 2021, up from a record 4.98 BCFD in 2019 and below its June forecast of 2020

In 2021, it was 7.31 BCFD.

Carbon emissions from burning fossil fuels are expected to fall from 5.130 billion tonnes in 2019, the lowest level since 1992, to 4.507 billion tonnes in 2020, the lowest level since 1983, and then to follow

Increase in coal use to 4.775 billion tons by 2021.

Demand is down and the electricity market favours renewables

The COVID-19 pandemic shows the power market’s preference for renewables in the face of falling demand, and the clean energy transition is likely to accelerate, Moody’s reports.

“Coal generation has continued to decline, while renewable energy has shown greater resilience in key markets in the United States, Europe, China and India,” the report said.

As a result of the blockade, electricity demand in India has fallen by 20 per cent, which has had a significant impact on coal production.

Both business and household electricity demand are expected to be severely affected by the recession and weaker expectations for long-term growth. Conventional energy production, such as coal and oil, also declined, the agency said.

Worldwide, renewable energy accounts for most of the recent new capacity, which continues to displace coal-fired power. Moody’s said the trend was expected to continue as electricity demand fell sharply as a result of the blockade.

“Covid-19 could have a ratchet effect, limiting any rebound in coal production and accelerating declines in the US and Europe for several years,” the rating agency said.

Moody’s also predicts that increased use of biofuels, electric cars and improved engine efficiency will increase the likelihood that oil demand will flow over time. While most developed countries already have targets and incentives for rapid adoption of electric vehicles over the next decade, India has yet to enact such a policy.

Renewable energy growth hit a record high in 2019

On June 17, the 69th edition of THE BP Statistical Yearbook on World Energy was released. The Yearbook points to continued strong growth in renewable energy. Renewable energy, led by wind and solar, is growing at record levels, accounting for more than 40% of primary energy growth in 2019. Meanwhile, coal consumption has fallen for the fourth time in the past six years, and its share of the global energy mix has fallen to its lowest level in 16 years.

But the structural picture remains grim. Although coal’s share fell last year, it is still the biggest source of electricity, accounting for more than 36% of global output. Renewables, by contrast, account for only 10 per cent, and will need to grow even more strongly over the next three decades to decarbonise the sector.

More worrying is the trend in carbon emissions. Carbon emissions growth slowed to 0.5% in 2019, a lower rate that suggests some optimism. But this deceleration comes against the backdrop of a huge 2.1 per cent increase in carbon emissions in 2018. As the world emerges from the coVID-19 crisis, the energy transition will also require decisive changes towards a more sustainable path.

To achieve net zero emissions by 2050, the world would need to reduce carbon emissions by the same amount every other year for the next 25 years, or 2.6 billion tonnes, the yearbook says.

This can only be achieved through a fundamental shift in behaviour, namely through more efficient use of resources and energy, and the implementation of all the technologies that are available in zero and low carbon energy, including renewable energy, electrification, hydrogen, CCUS (carbon capture and storage), bioenergy, and more.

In terms of consumption, China has become the largest contributor to global energy consumption growth, accounting for more than three quarters of global net growth. In the net zero vision, China’s energy policy choices and paths will directly affect the future pattern of global energy consumption.

What will affect the cable life?

Popularity has very high power, manufacturing from all walks of life cannot leave the electricity, the power is inseparable from the cable, so the service life of the cable will directly affect the safety of production, the service life of the cable is determined by the oxidation induction period of sheath material, use 20 years general cable design, real life is far greater than this value.
What are the factors that lead to reduced cable insulation?
1. External damage
From the operation analysis in recent years, especially in the rapid economic development today, a considerable number of cable faults are caused by mechanical damage.
2. Damp insulation
This is also common, usually at the end of a cable in a buried or drain pipe. For example: cable joints made unqualified and in humid climate conditions to do the joint, will make the joint water or mixed with water vapor, for a long time under the action of the electric field to form water branches, gradually damage the cable insulation strength and cause failure.

3. Chemical corrosion
Cables buried directly in areas with acid and alkali effects will often cause corrosion of the cable armor, lead or outer sheath. Long-term chemical or electrolytic corrosion of the protective layer will lead to failure of the protective layer and reduced insulation, and also lead to cable faults. Change: the cable corrosion situation of unit is quite serious.
4. Long-term over-load operation
In overload operation, due to the thermal effect of current, the conductor will inevitably heat up when the load current passes through the cable. Meanwhile, the skin effect of charge, the eddy current loss of steel armor and the insulation medium loss will also generate additional heat, which will increase the cable temperature. In long-term overload operation, excessive temperature will accelerate the aging of insulation and even the insulation will be broken down. Especially in the hot summer, the temperature rise of the cable often leads to the first breakdown of the cable insulation weakness, so in the summer, the cable faults are particularly frequent.

5. Cable joint failure
The cable joint is the weakest link in the cable line. The fault of the cable joint caused by the personnel’s direct fault (poor construction) often occurs. In the process of making the cable connector, if the original network such as the joint is not pressed tightly and the heating is not sufficient, the insulation of the cable head will be reduced, thus causing an accident.
6. Environment and temperature
The external environment and heat source in which the cable is located will also cause the cable temperature to be too high, the insulation to break down, and even the explosion and fire.
7. Other factors
Normal aging of cable body or other reasons such as natural disasters.

What is aluminium alloy power cable?

Aluminum alloy power cable is a new material power cable with AA8030 series aluminum alloy material as the conductor, adopting advanced technology such as special roll forming wire twisted production process and annealing treatment. Alloy power cable made up for the inadequacy of previous pure aluminium cable, although there is no improve the conductive properties of the cable, but the bending performance, creep resistance and corrosion resistance are greatly improved, to ensure that the cable for a long time to keep continuous stable performance when overload and overheat, the AA – 8030 series of aluminum alloy conductor, which can greatly improve the conductivity of the aluminum alloy cable, high temperature resistance, and solves the problem such as pure aluminium conductor, creep. The conductivity of aluminum alloy is 61.8% of that of copper IACS, the most common reference material. But at the same volume, the actual weight of an aluminum alloy is about a third that of copper. Therefore, the weight of the aluminum cable is about half that of the copper cable with the same load flow. The use of aluminum cable instead of copper cable can reduce the weight of the cable, reduce installation costs, reduce equipment and cable wear, making installation easier.
Aluminum alloy cables add copper, iron, magnesium, silicon, zinc, boron and other alloying elements into the electrical aluminum. At the same time, through process adjustment, the mechanical properties of aluminum alloy conductors are greatly improved to avoid the problems of low elongation, poor creep resistance and poor flexibility of pure aluminum conductors and increase the connection reliability of the cable system. In addition, keep the electrical properties of aluminum alloy and electrical aluminum conductor equal, at 61%IACS above.
Alloy power cable made up for the inadequacy of previous pure aluminium cable, although there is no improve the conductive properties of the cable, but the bending performance, creep resistance and corrosion resistance are greatly improved, to ensure that the cable for a long time to keep continuous stable performance when overload and overheat, the AA – 8030 series of aluminum alloy conductor, can significantly improve the conductivity of the aluminum alloy cable, high temperature resistance, at the same time solve the pure aluminium conductor electrochemical corrosion, creep, etc.
The conductivity of aluminum alloy is 61.8% of that of copper IACS, the most common reference material. But at the same volume, the actual weight of an aluminum alloy is about a third that of copper. . Therefore, the weight of the aluminum cable is about half that of the copper cable with the same load flow. The use of aluminum cable instead of copper cable can reduce the weight of the cable, reduce installation costs, reduce equipment and cable wear, making installation easier.
Aluminum alloy power cable has good mechanical properties and electric properties, it can be widely used various fields of national economy, such as common people residence, high-rise buildings, elevators, both large supermarket shopping malls, subway, airport, railway stations, hospitals, Banks, office buildings, hotels, postal telecommunications building, exhibition hall, library, museum, ancient buildings, schools, electricity, building, public places of entertainment, tunnels, underground buildings, warehouses, etc., can also be used for metallurgy, steel, coke, coal mines, power plants, power transmission and transformation station, shipbuilding, petroleum, chemical, aerospace, military, medicine, nuclear power plants, paper and other industries, And home appliances, cars, public transportation, and so on.

CRU upgraded China’s optical fiber and cable market demand forecast

With the novel Coronavirus epidemic under rapid control in China and the policy requirement to speed up the construction of new infrastructure such as 5G and big data center, the three domestic operators have also substantially increased the capital expenditure related to 5G. All these have provided further room for the growth of demand for optical fiber and cable.

Economic recovery CRU raised China’s optical fiber and cable market demand forecast

Michael Finch, director of CRU cables, said that given the latest statistics, worldwide demand for cable is expected to contract by 12-13 per cent year-on-year in the first quarter, falling below 100 million core kilometres, the lowest level since the fourth quarter of 2015.

Looking at the Chinese market, Michael Finch points out that demand for fiber optic cable in China has collapsed in Q1, down 18.6% year on year. Meanwhile, In Q1 of 2020, China will account for only 44 percent of the global demand for optical cable, compared with 53 percent in the same period of 2018.

Michael Finch said, “While fTTX-related demand continues to weaken, increased capital spending and a greater focus on 5G will support growth in China’s fiber demand. So we think the market will be brighter for the rest of 2020.”

It is clear that the signs of China’s economic recovery are becoming more and more obvious, and all eyes are now on the bidding of China’s three major operators. Against this backdrop, CRU raised its forecast for the Chinese market in 2020, with a projected demand decline of 5.7%. Michael Finch noted that CRU had forecast a 9% decline in February.

According to Michael Finch, China’s naked fiber market will be dominated by destocking in 2020, and the country’s naked fiber production is expected to fall 14 percent for the full year, while fiber optic cable production will fall 5 percent. Meanwhile, Michael Finch notes that despite the difficulties, many Chinese manufacturers will seek opportunities to expand exports this year.

In asia-pacific, excluding China, overall demand will remain weak in 2020, especially in India. In addition, in The North American market, higher demand growth was supported by regional protection and increased capital spending by U.S. carriers such as Verizon. However, in the European market, due to the impact of Q1 and Q2 epidemic, the demand showed a significant decline. “The delay in 5G deployment across Europe and the Asia-Pacific region has also affected the demand for fiber optic cables in the region to some extent.” Michael Finch says.

According to Michael Finch, operators are experiencing certain performance and financial pressures as a result of the outbreak, which will affect their investment and deployment plans. According to the latest estimates, global demand for optical fiber and cable is expected to drop by 3.6% in 2020, compared with a 1.9% decline in the absence of the epidemic. However, CRU also raised its market forecast for 2021 to 10.5% from 9.3%.