Sunday 28 February 2021

How can I connect a generator with an automatic transfer switch to a house with 2 electric meters?

How can I connect a generator with an automatic transfer switch to a house with 2 electric meters?

A lot depends on the topology you already have. Why are there two meters? Are they on the same phase? or (oddly) two? Presumably there are two distribution boards? do you actually need generator power on both of them?

Let us assume single phase, 240V. You want someting like this:

The changeover contactor will be 8-pole, 4NO, 4NC

What is the role of Damper Winding?

What is the role of Damper Winding?

 DAMPER WINDING IN SYNCHRONOUS MACHINE Damper windings helps the synchronous motor to start on its own (self starting machine) by providing starting torque.”

damper winding because of its additional property of damping out any oscillation that might be caused by sudden changes in the load on the rotor when in synchronism. Adjustment to load changes involves changes in the angle by which the rotor field lags the stator…”

Thursday 4 February 2021

Electrical Distribution Board installation

A electrical distribution board (or panel board) is a component of an electricity supply system which divides an electrical power feed into subsidiary circuits, while providing a protective fuse or circuit breaker for each circuit, in a common enclosure.Normally, a main switch, and in recent boards, one or more Residual-current devices or Residual Current Breakers with Over current protection will also be incorporated.


electrical distribution board are sometimes known as: breaker panels fuse box, fuse board, circuit breaker panel, consumer unit, or CU, panel board The branch distribution boards are used for further distribution of supply to various sub circuits. These are also provided with fuses at the commencement of sub circuit.


The Electrical Distribution In Distribution Board

The neutral is also further distributed to various sides from the neutral link. One or two spare sub circuits of the same capacity should be provided on each distribution board and branch distribution board for future requirement.

The current rating of circuit, size of fuse element and detail of circuits controlled by each distribution board should also be marked.

Strip the wire only enough to make the connection to the main breaker terminal lugs. The black and red wires are the feeder wires in this photo with the black wires being one of the hot feeds and the red wires being the other.

Steps to Install electrical distribution board

•    You must have to install the feeder pipe at first.

•    Install the connector into the panel

•    If you’re using metal pipe, place a plastic bushing over the connector threads.

•    Level the panel and insert screws through the holes provided in the back of the panel

•    Using a tape, pull the electrical feeder wires through the feeder pipe.

•    Leave enough wire to get to the opposite side of the panel.

•    Bend the two black wires to shape them for easy installation to the main breaker.

•    Excess bare wire leaves a safety hazard where the wires can come in contact with other wires and cause a short circuit.

•    Connect the neutral wire to the neutral buss. The neutral buss is located on either side of the breakers. It is a silver-colored bar with many smaller screws and connection points

•    Connect all of the green and bare copper wires to the ground buss bar.

•    If you bend the wires ahead of time, you’ll have a nice, neat wire installation that looks uniform.

•    Next, install the circuit feeds to the branch circuit breakers.

•    Connect the appropriate sized wire to the correctly rated. breaker. Bend the wires so that they keep a neat appearance when the installation is complete.


Some Special Things to Consider on Installing Distribution Broad

5 An iron clad enclosed pattern main switch is installed on the main board. The main board should be installed as near to the service board as possible and also near to the commencement of supply.

The height of the main switchboard should be so as to facilitate in its operation for isolating the supply to the building by the consumer.

The normal height of from ground level should be 1.5 meter. Seasoned teak wood or other durable wood with solid back impregnated with varnish of approved quality is used.

All joints of board should be dovetailed. The main switch board which contain relevant circuit breakers should be concealed in the wall thickness in flush with the surface of the wall.

The service board or energy meter board and main board close to each other and the box where the two boards are installed should be provided with shutter having glass window for meter reading and general inspection.




A electrical distribution board (or panel board) is a component of an electricity supply system which divides an electrical power feed into subsidiary circuits, while providing a protective fuse or circuit breaker for each circuit, in a common enclosure.Normally, a main switch, and in recent boards, one or more Residual-current devices or Residual Current Breakers with Over current protection will also be incorporated.

electrical distribution board are sometimes known as: breaker panels fuse box, fuse board, circuit breaker panel, consumer unit, or CU, panel board The branch distribution boards are used for further distribution of supply to various sub circuits. These are also provided with fuses at the commencement of sub circuit.


The Electrical Distribution In Distribution Board

The neutral is also further distributed to various sides from the neutral link. One or two spare sub circuits of the same capacity should be provided on each distribution board and branch distribution board for future requirement.

The current rating of circuit, size of fuse element and detail of circuits controlled by each distribution board should also be marked.

Strip the wire only enough to make the connection to the main breaker terminal lugs. The black and red wires are the feeder wires in this photo with the black wires being one of the hot feeds and the red wires being the other.

Steps to Install electrical distribution board

•    You must have to install the feeder pipe at first.

•    Install the connector into the panel

•    If you’re using metal pipe, place a plastic bushing over the connector threads.

•    Level the panel and insert screws through the holes provided in the back of the panel

•    Using a tape, pull the electrical feeder wires through the feeder pipe.

•    Leave enough wire to get to the opposite side of the panel.

•    Bend the two black wires to shape them for easy installation to the main breaker.

•    Excess bare wire leaves a safety hazard where the wires can come in contact with other wires and cause a short circuit.

•    Connect the neutral wire to the neutral buss. The neutral buss is located on either side of the breakers. It is a silver-colored bar with many smaller screws and connection points

•    Connect all of the green and bare copper wires to the ground buss bar.

•    If you bend the wires ahead of time, you’ll have a nice, neat wire installation that looks uniform.

•    Next, install the circuit feeds to the branch circuit breakers.

•    Connect the appropriate sized wire to the correctly rated. breaker. Bend the wires so that they keep a neat appearance when the installation is complete.


Some Special Things to Consider on Installing Distribution Broad

5 An iron clad enclosed pattern main switch is installed on the main board. The main board should be installed as near to the service board as possible and also near to the commencement of supply.

The height of the main switchboard should be so as to facilitate in its operation for isolating the supply to the building by the consumer.

The normal height of from ground level should be 1.5 meter. Seasoned teak wood or other durable wood with solid back impregnated with varnish of approved quality is used.

All joints of board should be dovetailed. The main switch board which contain relevant circuit breakers should be concealed in the wall thickness in flush with the surface of the wall.

The service board or energy meter board and main board close to each other and the box where the two boards are installed should be provided with shutter having glass window for meter reading and general inspection.

Monday 25 January 2021

What is protective relay?

 

Protective Relay

A protective relay is a device which initiates the circuit breaker to cut or off the faulty circuit from the healthy system. It acts just like a ‘ silence guard’, when any fault occurred in a system, the relay operates to close the trip circuit of the breaker and the breaker disconnects the faulty circuit.

Relay is the sensing unit of the electrical power system just like the brain of a human being which senses cold and hot things by touching it similarly, relay sense the abnormality in the system and gives trip command to the circuit breaker in order to disconnect the faulty section from healthy section.

A typical relay circuit is shown in fig. There are three parts in the relay circuit :-



  1. First part is, the primary winding of a current transformer (C.T ) which is connected in series the line.
  2. Second part , secondary winding of C.T is connected in series with relay operating coil.
  3. Third part is the tripping circuit which may be either AC and DC source of supply, trip coil of the circuit breaker and relay stationary contacts are connected in series connection.

Now describe, how the relay disconnects the faulty circuit . 

Suppose when a short circuit occurs at a point F, on the line, the huge current  flows in the line. Hence, a heavy current  flow through the relay coil, causing the relay to operate by closing its contacts. Result complete the tripping circuit of the breaker and making the circuit breaker open.

Relays are very important for protection of the electrical system and any damage occurring to the costly equipment's of a substation of any industry. 


-eeeaf team



Wednesday 28 October 2020

How do power companies generate electricity?

 In a variety of ways, usually, depending on the region. The vast majority of it is generated by magnetic induction, but some is generated by the photoelectric effect. I'll try to be comprehensive in this answer.

First, generation of electricity by magnetic induction:

The concept is relatively simple, and in practice it's surprisingly simple, too. While the generator depicted above is a pretty poor generator, it demonstrates the concept okay. The math behind magnetic induction is, in differential form (easier from an electromagnetics standpoint),

or in integral form (easier from a systems analysis standpoint)

Where B is magnetic flux density, phi is total magnetic flux through the coils, the big E is electric field and the curly E is voltage.

Here's how they do it in practice.
By far the cheapest per kilowatt-hour is hydro-electric power.

Quite simply, it uses gravity to naturally let water fall, and the moving water turns a turbine to generate electricity by magnetic induction. It's cheap per kilowatt-hour because there's no throttle time issues and no fuel. It can provide both baseline (low-power usage) and peaking (high power usage) generation. As long as it rains enough in the region, the reservoir will fill up without any human energy input.

A lot of our electricity is generated in coal power plants.

This power plant takes coal and burns it, using the heat to boil water and create high-pressure steam, which high pressure steam gets forced through a turbine, which generates electricity by magnetic induction.

Coal is pretty disgusting, by the way, but it's cheap unless you charge for the pollution. Coal power plants usually provide baseline power, since it requires incrementally more coal per extra bit of power. Coal for peaking is more expensive.

There are other systems in a coal power plant to make the process more efficient and have cleaner output, but those are a discussion for another question.

For peaking power, we often use natural gas generators.

It's similar to how the coal power plant works, except that it gets to double-dip on power generation -- first, the combustion reaction turns a turbine, and second, the hot exhaust boils water to turn a steam turbine.

Gas is expensive compared to coal, but the first turbine throttles up really quickly and the second within a few minutes, and it can be throttled up and down very easily compared to coal. As such, it makes for a great peaking generator.

In some areas, baseline power is provided by nuclear power plants.
Nuclear power is remarkably similar to the others, as it's a thermal power generator.


The major conceptual difference is that the heat comes from 
Radioactive decay. Nuclear makes an excellent, clean baseline power source, and the major issues are failsafe systems (prevent meltdowns) and where to store the spent (still radioactive, but not enough to work in this configuration) fuel rods. However, it isn't very good at throttling up and down, so it sticks to baseline power generation for the most part.

I believe the biggest obstacle to deployment of more nuclear power is NIMBYism -- "Not In My Back Yard" opposition.

Next up, we have wind power.

In principle, it's even simpler than a hydroelectric plant. For newer systems, it's pretty cheap. The wind turns some great big blades, which turn a generator. The most expensive part of wind power is probably the land area that it has to take up per unit of power. Another issue with wind is that in most places it can be pretty variable, meaning you can't at-will throttle it up and down, and it may not be producing power all the time. If you have a very diverse set of locations for wind generators connected to a grid, it can work well, but if you rely on a single location the generation is a little intermittent.

If you want to know a lot more about wind power, ask Michael Barnard.

Keeping with magnetic induction, some companies have been using concentrated solar-thermal power. The concept is, again, a thermal power system, but instead of burning fuel it concentrates sunlight on to a target to heat it up. Think of the way you used to burn ants with a magnifying glass, only switch the magnifying glass for a parabolic mirror, and make it a lot bigger, and that's how solar-thermal works. It comes in different forms, but the concept is the same in all cases.

Modern systems have a salt target that melts and stores the heat, allowing the power generation process to continue for several hours after the sun goes down.

Last, I'll talk briefly about photovoltaic power, which uses the photoelectric effect instead of magnetic induction.

The basic concept is that light can knock charge carriers out of a bound state in a material, if individual photons comprising that light have enough energy to do so. In a photovoltaic panel, we use a semiconductor p–n junction and make the light get absorbed in the depletion region of that junction where there are no native free charge carriers. The light "generates" charge carriers (knocks them off of the atoms holding them) and they diffuse to the electrodes. It generates DC power.

I personally have a lot of interest in photovoltaics. (See: Jacob VanWagoner's post in X-Ray Visions for an interesting lecture on conversion efficiency, Jacob VanWagoner's answer to Is solar power becoming more efficient? and many other things I've answered related to solar panels.) While they suffer the same limitation of not having 100% uptime as wind power, the two major advantages I see are distributed power generation that takes up no real usable space, and that the panels tend to generate the most at the time of highest demand -- the afternoon, when everybody is running air conditioning.

Which ones are used most? Depends on where you live.

Colorado's Electricity Portfolio

Wednesday 30 September 2020

How to Design Solar Led Street Light System?

 Solar technology is not a new technology, it was developed in 17th century B.C, and this technology has marked its presence in both developing as well as developed countries. Electric Street lights consume more energy as they use HD lamps. Today we have everything that work with solar energy like solar-powered buildings, vehicles, solar LED street lights, etc., for energy conservation.

Nowadays a new range of solar LED Street lighting make their presence felt everywhere and these lights are environmentally friendly and are easy to install and give high-intensity LED output. The solar LED street lights system convert sun energy to electricity and the system is prompted to turn on as the darkness approaches. Therefore, these lights automatically switch on after the sunset and after sunrise it switches off.

Solar Street Light

Solar Street Light

Design of Solar LED Street Light System

Blockdiagram of Solar LED Street Light

Design of Solar LED Street Light

The solar street lights operate from night until morning. The LED lamp automatically switches on after the sunset and switches off after the sunrise. This system design consists of the following parts:

  • Solar panels
  • LED light
  • Rechargeable battery
  • Controller
  • Pole
  • Interconnecting cables

Solar Panels

In solar street lights, the solar panel is one of the most important parts, and it is also known as solar photovoltaic cell. These cells are of two types: poly crystalline and mono crystalline. Compare to the poly crystalline, mono crystalline conversion rate is higher. Solar panels use light energy from the sun used to convert solar energy into electricity, which can be used to run many applications.

Electrical connections are made in series to accomplish an output voltage and to provide a current facility connections are made in parallel. The majority of modules use silicon or wafer based crystalline silicon but most of these solar panels are inflexible.

LED Light

In modern solar street lights, LEDs are used as lighting source and LED provide much brighter light with lower energy consumption. The energy utilization of LED fixture is lower than the HPS fixture, which is generally used in traditional street lights. Compare to the other HD lamps, and these lights do not emit light in all directions. The directional uniqueness of the LEDs will affect the design of lamps.

The output of the single LEDs is less than the other lamps like compact fluorescent and incandescent lamps but a set of LED lights gives bright light than these two. LED lights offer many benefits like Long life, durability, Eco-friendly and zero UV emissions.

Rechargeable Battery

Rechargeable battery is a type of electrical battery or accumulator and its electro mechanical reactions are reversible so it is called as secondary cell. Usually, there are two types of batteries: lead acid battery and gel cell deep cycle battery.

In solar LED street lights, a battery is used to store electricity from the solar panel during the day time to provide energy in the night time. The capacity and lifetime of the battery is very important as they affect the backup power days of the lights.

Controller

In solar LED street lights, a controller is very important as it usually decides to switch on or switch off the lighting and charging. Some modern controllers are programmable and are used to decide a suitable chance of lighting, dimming and charging. The Controller consists of a battery charger, a secondary power supply, a Led lamp driver, a driver, a protection circuit and a MCU.

The controller also controls the battery from overcharging and under charging conditions. By receiving the power from solar panels it continuously charges the battery in day time and while in evening it supplies the battery power to set of LED street lights.

Pole

For every street light, a strong pole is necessary, especially for a solar street light, there are some components like fixtures, batteries and panels mounted on the top of the pole, and input power consumption is 7.2 watt (LED). In solar street lights, the input operating voltage is 12V DC nominal system voltage, and the light output at the height of 12 feet is min of 09 LUX (unit of luminance).

Interconnecting cables

The battery box, Led light and solar panel are all fixed on the top of the pole and they are interconnected with cables. The cable for this LED system includes a PV module to the controller, and from controller to the battery and lamps. The cable size and lengths depends on the current being carried to the lights and the height of the pole.

With assembling all the above components into a one integrated system results the complete solar LED light system which uses sunlight energy to power the LED lamps fitted on street poles.

Solar LED Street Light Applications

  • Area lighting
  • Airport lighting
  • Hospital parking
  • Parks and playground parking
  • Parking lot lighting
  • Highway road way lighting
  • Street lighting
  • Security light
  • Highway and ramp lighting
  • Bridge lighting
  • Residential lighting
  • Industrial lighting
  • Commercial lighting

LED Lights offers the following Advantages:

  • Require fewer systems for installation.
  • Offers high lighting output when compare to the conventional lights.
  • Requires less time for installation and needs fewer systems.
  • Offers Long shelf life and low maintenance.
  • Offers pollution free ambience.
  • Provides provision of portability.
  • Comes with two year full system warranty.

Disadvantages

  • Initial investment is high when compared to the conventional lights.
  • The dust, snow or moisture can mount up on the PV panels, and thus reduces the energy production.
  • The rechargeable batteries need to be replaced several times.
  • Solar system costs reasonably high, and therefore,, the risk of theft is higher.

This is all about the solar LED Street light and its applications. We hope that you have got clear understanding of this topic, and if you have any doubts on this topic, you can contact to us. And, don’t forget to post your views and feedback on this article in the comment section below.

Saturday 26 September 2020

World’s largest floating solar plant connected in China

 Chinese state-owned developer CECEP has completed a 70MW floating solar project - the largest in the world - at a former coal-mining area of Anhui Province, China, in collaboration with French floating solar specialist Ciel & Terre.

The project, spread across 13 separate islets on an area of 140 hectares, was completed in late 2018, with grid-connection, tests and commissioning carried out this month at the project site in the Lianghuai mining subsidence area, Yongqiao District, Suzhou City.

EPC services were provided by China Energy Conservation Solar Technology and the China Energy Engineering Group Shanxi Electric Power Design Institute. A brand new 18km 110V overhead line was also built for the grid connection of the plant, which is expected to generate up to 77,693MWh of electricity in its first year, equivalent to the power consumption of nearly 21,000 households. 



While the complete facility in Anhui is said to currently be the largest floating PV plant on the same reservoir in the world, nearby, China-based firm Three Gorges New Energy has already partially connected a 150MW floating PV project to the grid, which is likely to become the largest plant globally once fully commissioned.

Equipment

The CECEP system was built using Ciel & Terre's Hydrelio floats, which are locally produced to minimize emissions, optimise logistics costs and offer local employment.

The project uses monocrystalline modules from Chinese manufacturer LONGi Solar, as confirmed by a C&T spokesperson to PV Tech. Central inverters have also been put on stilt platforms on the shoreline of the quarry lake so as not to interfere with neighbouring farm activity. Concrete poles support the electrical installation and 1,500 helical anchors were used for the project and buried at an 8-15 metre-depth to match the water body.

Ciel & Terre has already supplied its floating structure solution to GCL's 32MW FPV plant in Anhui province. It has also recently supplied a 9.8MW PV project featuring rooftop and floating elements in Cambodia.

AC 12V-0-12V transformer