electrical engineering : power systems

Power losses reduction in electrical distribution

<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: center;"><b>Reducing power losses by optimizing equipment locations</b></div><div></div><div style="text-align: center;"><img alt="power-losses" class="alignleft size-full wp-image-1243" height="151" src="http://engineering.electrical-equipment.org/wp-content/uploads/2009/06/power-losses.jpg" title="power-losses" width="247" /></div><div style="text-align: center;"></div><div style="text-align: center;"> Do you realize that power losses in a electrical installation could represent up to 7 %  of the electrical consumption ?</div><div style="text-align: center;"></div><div style="text-align: center;">LV cables and transformers are the most contributors to these operating losses, around 95 % as shown here below</div><div style="text-align: center;"></div><div style="text-align: center;"><br />
</div><div style="text-align: center;"></div><div style="text-align: center;"><br />
</div><div style="text-align: center;"></div><div style="text-align: center;"><br />
</div><div style="text-align: center;"></div><div style="text-align: center;"><span id="more-1240"></span>Of course, low losses transformer can be used to reduce the energy dissipation, a study should then be done to assess the payback period.</div><div style="text-align: center;"></div><div style="text-align: center;">There’s also one rule that is sometimes forgotten during the design, it’s mentioned in some standards (French standard – NF – C15-100) or codes of practice: place the transformer and the main low voltage switchboard as close as possible to their load centre (centre of gravity of the consumers).</div><div style="text-align: center;"></div><div style="text-align: center;">Most of the time,  you can reduce up to 30% the losses and consequently carbon emissions while using less cables that’s to say less investment costs. For example, the design in such a way for a food and beverage plant will save 120 k€ over 15 years and to divide almost by 3 the quantity of installed cables.</div><div style="text-align: center;"></div><div style="text-align: center;">However, it’s not always possible to choose the location of the transformer and the main switchboard because it’s sometimes imposed by the architect but this rule can also be applied to the sub-distribution boards, and contribute then to reduce the power losses between these switchboards and their supplied consumers.</div><div style="text-align: center;"></div><div style="text-align: center;">An electrical Software such as ID-Spec Large can help to determine the best location of the electrical equipment according to the implementation of the consumers on the CAD building layout (see the blue circle that represents the load centre of the MV/LV substation) and give an indicator of the quantity of cables during the design of the electrical installation.</div><div style="text-align: center;"></div><div style="text-align: center;"><br />
</div><div style="text-align: center;"></div><div class="wp-caption aligncenter" id="attachment_1245" style="text-align: center; width: 599px;"><img alt="ID-spec-large-software" class="size-full wp-image-1245 " height="442" src="http://engineering.electrical-equipment.org/wp-content/uploads/2009/06/id-spec-large-software.jpg" title="id-spec-large-software" width="589" /><br />
<div class="wp-caption-text">ID-spec-large-software</div></div><div style="text-align: center;"></div><div style="text-align: center;"><br />
</div><div style="text-align: center;"><a href="http://engineering.electrical-equipment.org/tag/power-losses">source </a></div></div>

Power losses reduction in electrical distribution

Reducing power losses by optimizing equipment locations Do you realize that power losses in a electrical installation could represent up to...

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First Order Transient Circuits

<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">first order circuit are those circuits whose response can be expressed by a first order differential equations.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Example of such circuits include the RL and RC circuits</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RL circuit : circuit that contains an indicator and a resistor.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RC circuit : circuit that contains a capacitor and resistor</div><div style="text-align: justify;"><br />
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This is a first order linear ordinary non-homogenous differential<br />
equation describing the response of the capacitor voltage.<br />
It is first order because the highest degree of derivative is one.<br />
it is called linear because the differential equation is linear<br />
function of (dvc /dt) and vc(t)<br />
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To solve this circuit I'm going to use the differential equation approach. I'm concerned with the<br />
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voltage across the capacitor at <a href=""><img align="top" alt="LaTeX Code: V_c(0^-) " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-0.png" title="LaTeX Code: V_c(0^-) " /></a> and <a href=""><img align="top" alt="LaTeX Code: V_c(0^+) " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-1.png" title="LaTeX Code: V_c(0^+) " /></a><br />
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At position 1 before the switch is thrown <a href=""><img align="top" alt="LaTeX Code: V_c(0^-)=0 " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-2.png" title="LaTeX Code: V_c(0^-)=0 " /></a><br />
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At position 2 after switch is thrown I have the following from KCL:<br />
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<a href=""><img align="top" alt="LaTeX Code: \\frac{6-V(t)}{12k} = C\\frac{dv}{dt} + \\frac{V(t)}{6k} " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-3.png" title="LaTeX Code: \\frac{6-V(t)}{12k} = C\\frac{dv}{dt} + \\frac{V(t)}{6k} " /></a><br />
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This reduces to: <a href=""><img align="top" alt="LaTeX Code: \\frac{dv}{dt} + 2.5V(t) = 5  " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-4.png" title="LaTeX Code: \\frac{dv}{dt} + 2.5V(t) = 5  " /></a><br />
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My problem is that I know that this is correct but I don't know how to put it all together.<br />
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I know that the solution is of the form:<br />
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<a href=""><img align="top" alt="LaTeX Code: K_1 +K_2e^{-t/t_c} " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-5.png" title="LaTeX Code: K_1 +K_2e^{-t/t_c} " /></a><br />
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The answer is <a href=""><img align="top" alt="LaTeX Code: V(t)=1.33 -1.33e^{-2.5t}V " border="0" src="http://www.physicsforums.com/latex_images/13/1349535-6.png" title="LaTeX Code: V(t)=1.33 -1.33e^{-2.5t}V " /></a><br />
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How do I extract this from my work?<img alt="" border="0" class="inlineimg" src="http://www.physicsforums.com/images/smilies/laughing.gif" title="Laughing" /><br />
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First Order Transient Circuits

first order circuit are those circuits whose response can be expressed by a first order differential equations. Example of such circuits i...

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Circuit Active Elements

<div dir="ltr" style="text-align: left;" trbidi="on"><span style="color: red; font-size: large;">There are 4 types of active elements (sources)</span><br />
<div style="color: red;"><span style="font-size: large;"><br />
</span></div><div style="color: red;"><span style="font-size: large;">1. Independent voltage source:</span></div><div style="color: red;"><span style="font-size: large;"><br />
It is a 2-terminal sources that maintains a specific voltage across its terminals regardless of the current through it</span></div><div style="color: red;"><span style="font-size: large;"><br />
</span></div><div style="color: red;"><span style="font-size: large;"><br />
</span></div><div style="color: red;"><span style="font-size: large;">2. Independent current source:</span></div><div style="color: red;"><span style="font-size: large;"><br />
It is a 2-terminal sources that maintains a specific current through it regardless of the voltage across it terminals.</span></div><div style="color: red;"><span style="font-size: large;"><br />
</span></div><div style="color: red;"><span style="font-size: large;">3. Dependent voltage source:</span></div><div style="color: red;"><span style="font-size: large;"><br />
It is a 2-terminal sources that generates a voltage that is determined by a voltage or current at a specified location in the circuit.</span></div><div style="color: red;"><br />
</div><div style="color: red;"><span style="font-size: large;"> 4. Dependent current source:</span></div><div style="color: red;"><span style="font-size: large;"><br />
It is a 2-terminal sources that generates a current that is </span></div><div style="color: red;"><span style="font-size: large;"> determined by voltage or current at a specified location in the circuit.</span></div><div style="color: red;"><br />
</div><span style="color: red; font-size: large;">Basic Quantities</span><br />
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<span style="color: red; font-size: large;">(1) Electron :electron is a mobile charge carrier.</span><br />
<span style="color: red; font-size: large;"><br />
The electron is measured in coulumb [ C ]</span><br />
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</div><div style="color: red;"><span style="font-size: large;">(2) Current :</span></div><div style="color: red;"><span style="font-size: large;"><br />
the time rate of change of charge produces an electrical current</span></div><div style="color: red;"><br />
</div><span style="color: red; font-size: large;">the electric current is measured in Amper [A]</span><br />
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<div style="color: red;"><span style="font-size: large;">(3) Voltage :</span></div><div style="color: red;"><span style="font-size: large;"><br />
The voltage is defined as the work or energy (in Joules) required per unit charge to move a test charge though an element</span></div><div style="color: red;"><br />
</div><div style="color: red;"><span style="font-size: large;">(4) Power :</span></div><div style="color: red;"><span style="font-size: large;"><br />
Power is the time rate of change of energy.</span></div><br />
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<span style="color: red; font-size: large;">(5) Energy</span><br />
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<span style="color: red; font-size: large;">Passive sign convention</span><br />
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<span style="color: red; font-size: large;">Power can be absorbed or supplied by an element.</span><br />
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<span style="color: red; font-size: large;">Power is absorbed (or dissipated) by an element if the sign of power is (+)</span><br />
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<span style="color: red; font-size: large;">Power is supplied (delivered or generated) by an element if<br />
the sign of power is (-)</span></div>

Circuit Active Elements

There are 4 types of active elements (sources) 1. Independent voltage source: It is a 2-terminal sources that maintains a specific voltag...

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Optimization of Links – tie-up of GCC with European and African

Optimization of Links – tie-up of GCC with European and African

Linking GCC with the Arab grid and eventually to the European and Sub-Sahara grid is viable solution given the geo-political challenge •...

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Time Factor can play an important role

Time Factor can play an important role

• Demand in the GCC countries is seasonal. In winter time, i.e. during the month from October till mid of March there is surplus electricity...

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the Benefits of the Interconnection Project

<div dir="ltr" style="text-align: left;" trbidi="on"><div style="color: red;"><span style="font-size: large;">Enables interchange of energy between systems resulting in a<br />
lower total operating costs</span></div><div style="color: red;"><span style="font-size: large;"><br />
•Enables systems to share operating reserve so that each system<br />
can carry less spinning reserve</span></div><span style="color: red; font-size: large;"><br />
•Permits assistance from neighboring systems to cope with<br />
unforeseen construction delays and unexpected load growth</span><br />
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<div style="color: red;"><span style="font-size: large;">•Results in requirement for lower installed capacity in each of the systems while still supplying the load with the same level of reliability</span></div><div style="color: red;"><span style="font-size: large;"><br />
•Permits larger and more efficient generating units to be installedon the individual systems</span></div><div style="color: red;"><span style="font-size: large;"><br />
•Permits emergency assistance between systems to mitigate the effects of unforeseen contingencies such as catastrophic multipleoutages</span></div><span style="font-size: large;"><br />
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the Benefits of the Interconnection Project

Enables interchange of energy between systems resulting in a lower total operating costs •Enables systems to share operating reserve so th...

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Midal Cables Limited

<div dir="ltr" style="text-align: left;" trbidi="on"><span style="font-size: large;">•Midal Cables was established in 1977. It is presently one of the worlds largest<br />
producer of Aluminium & Aluminium Alloy Rod, Wires and Overhead Conductors with<br />
a rod capacity of 170,000 MT per annum.</span><br />
<span style="font-size: large;"><br />
• Metal Form is Midal’s wholly owned downstream subsidiary. Metal Form’s product<br />
range is Conform, Aluminium Clad Steel Wire, etc.</span><br />
<span style="font-size: large;"><br />
• Aluwheel is Midal’s major investment in aluminum wheel business. Aluwheel’s core products are Aluminum Wheels for Trucks and Passenger Cars</span><br />
<span style="font-size: large;"><br />
• Marketing & International Offices – Almost 100% of our products are<br />
exported through the offices in Bahrain, UK, Kenya, Malaysia and Canada supported<br />
by agents in over 50 countries.</span><br />
<span style="font-size: large;"><br />
• EHS Certification – In 1993 Midal Bahrain was the first manufacturing company to<br />
obtain ISO 9001-2000 certificate. Since then we were the first to obtain ISO<br />
14001:2004 and OHS AS 18001:1999 Certifications.</span></div>

Midal Cables Limited

•Midal Cables was established in 1977. It is presently one of the worlds largest producer of Aluminium & Aluminium Alloy Rod, Wires and...

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Satisfying Customers through the Supply Chain

<div dir="ltr" style="text-align: left;" trbidi="on"><div style="color: red;"><span style="font-size: large;">Different Products have different shelf life</span></div><div style="color: blue;"><span style="font-size: large;"><br />
</span></div><span style="font-size: large;"><span style="color: blue;">Fast Food has a shelf-life of 3 hours</span></span><br />
<span style="font-size: large;"><span style="color: blue;"> </span><br style="color: blue;" /><span style="color: blue;">Dairy Products have a shelf-life of approx 4 to 7 days</span></span><br />
<span style="font-size: large;"><span style="color: blue;"> </span><br style="color: blue;" /><span style="color: blue;">A hotel room waits for you only 24 hours before you confirm</span></span><br />
<span style="font-size: large;"><span style="color: blue;"> </span><br style="color: blue;" /><span style="color: blue;">Fresh fruits & vegetables have shelf-life of approx. 2 days</span></span><br />
<span style="font-size: large;"><span style="color: blue;"> </span><br style="color: blue;" /><span style="color: blue;">Expected average life around 50 years</span></span><br />
<br />
<span style="font-size: large;"><span style="color: red;">Electricity has ZERO shelf life</span></span><br />
<br />
<span style="color: blue; font-size: large;">Electricity cannot be stored effectively Generation should </span><br />
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<span style="color: blue; font-size: large;">exactly match demand Inter-regional grid can help in </span><br />
<br />
<span style="color: blue; font-size: large;">matching supply with demand Electricity has ZERO shelf life </span><br />
<br />
<span style="color: blue; font-size: large;">Shelf-life can be created for Electricity by inter connectivity of</span><br />
<br />
<span style="color: blue; font-size: large;"> Networks</span></div>

Satisfying Customers through the Supply Chain

Different Products have different shelf life Fast Food has a shelf-life of 3 hours Dairy Products have a shelf-life of approx 4 to 7 day...

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