It's Not Hard To Convert A Street Lamp Into An LED One
- Jul 24, 2018 -

In view of the current situation of high energy consumption, easy damage, difficult maintenance and safety hazards of small and old lighting lamps which have been installed in a large number of factories, campuses and residential areas, this paper proposes to solve the above problems by retaining the original power supply lines and the main street lamps by adding LED controllers and replacing LED lighters.

An example of an activity center shows that this scheme is feasible and effective.

With the global industrialization process accelerating, the growing demand for a variety of human resources, all kinds of to the development and utilization of resources on the earth is suffering the unprecedented overexploitation, as a result of ecological destruction and environmental pollution problem more and more serious, for our country, the shortage of resources per capita, the environmental capacity is limited, such problems as ecological fragile is particularly serious, if these problems can't be settled effectively, it will be greatly restricted the economic development of our country's space and sustainability.

Under this serious situation, "build a resource-conserving and environment-friendly society" has become a basic national policy of our country, and how to deal with the currently existing in a large number of high energy consumption equipment is a top priority, and all the update costly and laborious and waste of resources, so the energy-saving renovation, make it meet the requirements of energy saving is the only way out.

By testing the modified street lamp line, the article determines whether the original line has the use conditions.

Through the analysis of the internal structure and the force of the street lamp, it is concluded that the street lamp after the transformation is safe.

Based on the analysis of the configuration of the original street lamp, the optimal transformation scheme and implementation scheme are selected.

1. Power supply line inspection and load change analysis of street lamps

After years of operation, the power transmission quality of the power supply line will decrease, mainly in the two aspects of the increase of the resistance value of the line and the decline of the insulation performance. Therefore, at the beginning of the transformation of the street lamp, a comprehensive inspection of the power supply line is required.

1.1 check the line resistance value

Street lamp power supply three phase four wire system commonly used power supply in parallel, we first have to disconnect to street lamp power supply circuit in the transformer room, then temporary put three wire with a short center line, to combine each street lamp power supply circuit in disconnected from the main power supply circuit, only keep the line connected, and then at the far end with multimeter measured three root resistance between the wire and the center line.

Under normal circumstances three wire and resistance between the center line should be basically equal, and the measured resistance should number and the number of resistance calculations by {conductor resistance formula: R = rho (L/S, resistivity, rho = L = length (m), S = line load face (2).

The resistivity of a copper wire: immunization =0.0172;

The resistivity of aluminum wires is not much different from that of 0.0283}. If the measured resistance value meets the above requirements, the next insulation inspection will be carried out.

1.2 check the line insulation resistance

After the resistance check of street lamp line meets the requirements, disconnect the short connection between the fire line and the middle line, and keep all points in the line not connected to each other and no connection place. Then measure the insulation resistance of each line with megohm meter successively.

Conform to the requirements of the insulation resistance should not be less than 0.5 M Ω (especially the phase between line and line to ground insulation resistance should be greater than 0.5 M Ω, Central Line can be over 0.25 M Ω).

If the measured insulation resistance does not meet the above requirements, it indicates that the insulation layer of the main line road is seriously aging or the insulation layer is damaged, and the line should be repaired or replaced according to the actual situation.

1.3 load change analysis of power supply lines

The load change of power supply line is mainly caused by the change of street lamp power and line loss.

Under the same light intensity and light range of conditions, LED light source, power consumption is only about 50% of the power consumption of the metal halide light source, street light line loss will also be reduced by 75% (in the case of constant voltage, load power by 50%, the main way of current is reduced by 50%, according to the formula "loss power W = square x line resistance of line current (I)" line loss can be calculated value), it is not only beneficial to achieve the goal of saving energy and reducing consumption, but also eliminates the caused by power lines full load operation of the power supply circuit fever, poor contact, open tripping fault phenomena, such as

Therefore, the transformation of street lamp light source into LED will be very beneficial to the long-term stable operation of street lamp system.

2. Check the structural parts of street lamp body and analyze the force change

The structure of street lamp body includes base, lamp pole, lamp head and other appendages.

The materials of structural parts include metal, glass, plastic and so on.

The inspection of structural parts is mainly visual inspection, and the main inspection is whether the structural parts have corrosion, deformation, breakage and other phenomena that affect the appearance and structure stress.

Most street lamps will be damaged from local components after several years of operation. In the process of street lamp transformation, the damaged parts should be repaired or replaced so as to make the street lamps reach the use conditions after transformation.

The analysis of the stress change of the structure of street lamp is to test whether the main bearing capacity of street lamp meets the safety requirement.

During the transformation, the weight center of the lamp and the area facing the wind may change. When the weight center of the lamp moves down or stays unchanged, the area facing the wind shrinks or remains unchanged, the maximum torque at the root connecting the lamp pole and the base will remain unchanged or be reduced, meeting the original design requirements of the lamp pole for strength and deflection, thus ensuring the safety of the street lamp.

When the weight of the lamp is shifted to the heart and the windward area is increased, the maximum torque at the root connecting the lamp pole to the base is increased. It is necessary to verify whether the street lamp is safe as follows:

2.1 verify lamp rod strength

Determine the maximum gale speed U(level 12 =36M/S), calculate the wind pressure P = U2/1.6, calculate the headwind area S lamp body =(D+ D)*H/2 +S accessories +S lamps (where D is the outer diameter at the bottom of the lamp pole and D is the outer diameter at the top of the lamp pole;

H is the height of the lamp pole), and the weight center height of the lamp Hx = (2d+D)*H/3(D +D) is calculated, and the wind pressure torque of the lamp body M = P * S * Hx (the wind pressure torque of the lamp body will vary with the height.

The resistance moment of the cross section at the root of the lamp pole: W = hydra *(d4-d4)/32D, the allowable value of the lamp pole's root torque: [M] = W*[jing], which is the yield strength of the lamp pole material.

 

2.2 verify the rod deflection

The approximate calculation formula of conical rod as straight bar is: De = (d+ d)/2;

The moment of inertia of the cross section: I = elimination *[De4-(De-2t)4]/64(t is the material thickness);

Load at center of gravity: Q = M/Hx;

Deflection caused by wind pressure on street lamps: Fmax = QHx3/3EI (E is elastic modulus);

When the allowable value of rod deflection: [Fmax] = H/40 > Fmax, the rod deflection is safe.

Considering the factors such as the unevenness coefficient of wind speed, aerodynamic coefficient and the Angle between wind direction, lamp posts and lamps, the actual stress at the dangerous section and the deflection of the lamp roof are lower than the calculated results above. Therefore, after the above verification, the lamp pole design meeting the requirements is safe and reliable.

3. Parameter comparison and power selection between LED light source and traditional light source

At present, the light sources used by small street lamps that have been installed and used for many years are various and have different performances. The following table shows the technical parameters of LED light sources and various traditional light sources:

1

Through the comprehensive comparison of technical parameters of various light sources and the comparison of actual application results, it is found that LED light sources have high luminous efficiency, good color rendering performance, and the longest service life. 70W LED can replace 250W high pressure sodium lamp, or 300W mercury lamp, and achieve energy saving of over 70%.

Therefore, when selecting the power of the LED light source used in the transformation, one third of the power of the existing light source can be taken as the reference standard.

4. Design and implementation of street lamp renovation scheme

This paper mainly discusses the reconstruction scheme of small street lamps.

Small street lamp has the characteristics of low lamp height (the height of the lamp is 3 ~ 5 meters), diversified structure (both simple integrated lighting street lamp and complex and changeable landscape street lamp), etc., so the reconstruction plan should be designed according to the specific configuration of the original street lamp system.

It is necessary to consider not only the lamp structure of the original street lamp and the aesthetics after the transformation, but also the control of the reconstruction cost and the maximization of the existing resources.

Therefore, the design principle of the street lamp renovation scheme is: not to change the street lamp appearance or less;

Circulating makes full use of the original street lamp circuit and installation structural parts (maximize resource reuse);

Torque makes full use of the diversity of LED products (red, yellow, blue, green, white, etc.).

To meet the needs of transformation, the lighting body should be made by using LED lamp strips or lamp beads according to the internal structure of street lamps when necessary.

In view of energy-saving and environmental protection factors, timesaving control (full on busy and half on idle) is realized.

In order to make full use of resources, we can adopt the stepwise transformation method during the implementation of the scheme.

First of all, the original street lamp was disassembled and tested, and the light source and accessories that are still valuable for use were collected to repair part of the street lamp, so that it could be rebuilt after natural damage.

Street lamps that cannot be repaired are first transformed and have a good record of transformation.

Due to the modified street lamp fell more than 50% of the total power, so we can make full use of the original branch control circuit of three phase line, through can controller is easy to implement on the street lamp any switch control of double light source and three light source, it is not only beneficial to realize saving energy and reducing consumption, greatly extend the service life of LED lights.

After the completion of the street lamp renovation, the energy saving comparison table can be formed by recording data of power consumption at the early stage:

2

5, summary

According to this scheme, an activity center has completed 60 street light transformation, the original street light 120 w metal halide lamp dome light for 30 w LED spot light, original 40 w daylight lamp pole lamp 2 root for cylinder made of white article 5050 leds lamp (power of 20 w), and the dome light and light to realize time-sharing control, controlled by the theodolite street lamp dome light switch, light is controlled by the time controller for 6 ~ 12 lights at night, shut down after 12 o 'clock, the statistics to realize energy saving more than 75%.

The above successful cases prove that this LED street lamp transformation scheme is feasible and plays a guiding role in the transformation of old and old street lamps into LED street lamps.

2