Tuesday, September 26, 2023

Understanding How Power Roll-Outs or Shedding Work

 Power rolling blackouts, or load shedding, are when the demand for electricity or power exceeds the available supply. This causes instability in the grid as all the consumers attempt to pull the insufficient capacity, which may cause damage to essential power systems and further exacerbate the situation. The power utility company thus purposely shut the power off in selected areas to balance the demand-supply levels. The shedding reduces the chances of more prolonged blackouts, avoiding complete shutdowns and avoiding damage to the power grid.

Various reasons lead to the need for power shedding. The primary factor is damage to the power transmission lines, which are the primary distribution lines, to different factors like storms, earthquakes, and vandalism of critical power equipment. Another reason is the loss of a significant power generator due to equipment loss or a primary contributor. For example, countries that rely on different sources of power, like power, nuclear or hydroelectric, may require shedding if severe drought affects the hydroelectric generators due to reduced water levels or a nuclear plant requires maintenance.

Also, load shedding becomes necessary if the consumers increase consumption in a limited time. An example is changing consumer behavior or requirements, such as population increase, heat waves, or winter, where people use heating, ventilation, and air condition systems more than on regular occasions.

When the highlighted scenarios occur, the national or local utility responsible for electricity transmission shuts down some power distribution and feeder lines to maintain short-term and long-term power integrity, reliability, and safety. In countries facing scenarios requiring shedding, these utility firms work with the governments for planned rollout plans, with prior notice to the affected consumers. This enables the involved parties to access services like automated teller machines and gas stations.

The consumers are grouped in clusters, and the power is switched off for a group for a few hours, typically two. After the scheduled hours, the operator switches the power off for the next cluster using the feeder lines while the first group resumes regular supply. The rollout cycle continues until the load shedding is complete and the system is stable. The rollout process is either automatic or manual. Operators prefer manual rollouts as they are more controllable and easily adjusted to suit different scenarios.

The government and utility companies often attempt to reduce the chances of and the need for rollout. The typical method was incentivizing industries and owners of large buildings to reduce power use during peak periods and off-grid options like solar systems.

However, in almost all instances, the operators ensure critical areas like hospitals, law enforcement areas, and water systems retain regular power supply, with most of the rollout directed to households. Shedding in these places can have negative consequences. An example is the Texas Power Crises, where experts indicated that over 700 people died from factors emanating from extended blackouts like freezing after a snowstorm cut off power. However, living near the critical areas does not guarantee exemption from the rollouts, as sharing the power feeder line is not assured.

The effects of the rollout vary, but the primary one is the inconvenience of intermittent power supply. When too frequent, like during the heavy rains and storm season, when damage to the power season is more frequent, people experience a reduced quality of life due to limited access to regular household, social, and economic activities. The goal, however, is to ensure a reliable power supply over a more extended period.

Friday, August 11, 2023

Biofuels and How They Are Made

 Biofuels are a renewable source of energy that has been around for decades. The two most popular versions of biofuel are biodiesel and ethanol, representing the first generation of biofuels. Other biofuels include biogas, butanol, methanol, and wood.

Bioengineers manufacture biofuels using plant materials and other feedstock, generally called biomass. They first convert biogas and liquid biofuels before using them as an energy source. However, solid biofuels such as wood and wood waste can be used directly as a fuel source without conversion.

Biofuels have a much lower impact on the environment than traditional sources of fuel, offering a renewable and sustainable source of clean energy. As a result, they are often mixed with regular gasoline to make them more efficient and sustainable.

Biofuels have different modes of production, depending on their composition and intended use. For example, the manufacturing process of ethanol begins with the cultivation of starchy plants like corn, wheat, or soybeans. After harvesting, bioengineers process the crops to obtain the oils and sugar used in making biofuels. This stage of processing biomass for fuel production is called conversion. The conventional method of doing this is fermentation.

Corn is ground and mixed with water to obtain a starchy mix. Enzymes are introduced to this mix to reduce their cellular structure to simple sugars and watery forms. These simple sugars are then fermented with yeast to produce ethanol. Any leftover water in ethanol must be dried and exhausted before it is used as fuel for car engines; therefore, it must first undergo dehydration and distillation to remove any water content before it is suitable for use.

In biodiesel production, transesterification is used in place of fermentation. Fatty acid methyl esters (FAMEs) are the primary chemicals present in biodiesel. Transesterification is the method of disintegrating the triglycerides in oil or fat so that all that remains are the FAMEs.

Sodium hydroxide acts as a catalyst on a mixture of oil or fat and an alcohol like methanol to complete this process. After completing this process, heating and agitating the by-product produces glycerin and FAMEs. The glycerin is discarded, and biodiesel is the liquid that remains after the entire process of transesterification.

Biogas is a common fuel source in most power plants. It is commonly used for the generation of heat and electricity. Its production is a result of a process called anaerobic digestion. During this process, organic matter is decomposed in the absence of oxygen. As a result, carbon dioxide, a mixture of methane and other gasses that can be used for energy production, is obtained.

Regardless of the mode of production, ethanol and biodiesel must be purified and blended with gasoline or diesel fuel before use in a car engine as fuel. They are not used as primary fuel sources in cars because their level of efficiency as a standalone fuel does not measure up to that of fossil fuels. Therefore, they are only used as an additive or mixed with gasoline to increase their octane levels. An example of an ethanol and gasoline mixture that is well known for its use is E10, which consists of 10 percent ethanol and 90 percent gasoline and can aid in the higher performance of internal combustion engines.

Monday, March 27, 2023

How Capacitors Store and Release Energy

 Based in Southern California, Dianoush Emami has managed numerous construction and engineering actives, with a focus on complex utility and general facility projects. Dianoush Emami has guided various applications involving the transmission and distribution of high-voltage electricity.

One of the essential electrical components for storing energy is the capacitor. A battery is quick to charge, and relies on chemical reactions for the release of energy and thus has a slow discharge rate. By contrast the capacitor, as a circuit component, stores electrical energy temporarily via a process of distributing charged particles across a pair of plates, which creates a difference in potential. Requiring less time than a battery to charge, the capacitor is also able to release its energy very quickly.

Capacitors have a variety of uses, with mylar capacitors commonly employed in timer circuits such as alarm clocks and ceramic capacitors employed with high frequency applications such as X-ray or MRI equipment. Super capacitors are used in powering hybrid and electric vehicles, while those made of glass support high-voltage applications. Within these various capacitors, terminals connect with two metal plates that are separated by a dielectric, or a non-conducting substance.

Capacitors are engaged by being connected with a battery or other power source, with one plate connected to its negative terminal and one to its positive terminal. A good way of envisioning the capacitor and its storage and release of electrons is as a water tower connected to a water pipe. The tower stores water pressure when there is excess water that a community cannot readily consume, and releases water when it’s needed at a time of high demand.

Wednesday, March 8, 2023

Electrical Penetration Assemblies and Nuclear Plant Containment

 Dianoush Emami is a longtime California power consultant who provides electrical engineering expertise that boosts the safety and efficiency of power plants and transmission systems. One area of focus for Dianoush Emami is electrical penetration protection within nuclear power plants.

An electrical penetration assembly (EPA) comprises insulated electric conductors, module, aperture, and conductor seals. These ensure that electric conductors pass through a single hole within a nuclear containment structure while simultaneously delivering a pressure barrier between the containment structure’s inside and outside regions.

Each reactor within a plant may have numerous points where EPAs must be installed to feed signals through. Containment integrity is essential for preventing radiation leaks, and EPAs are rigorously built to withstand both existing and potential conditions within the reactor. Without that safety element, they can emerge as the weak point at which operational failure occurs.

Two critical elements of EPA performance are seals and interfaces. While epoxy seals are not typically an issue, the field cabling interface that is either embedded within the epoxy or used in terminating a cable is a distinct area of vulnerability.

Tuesday, February 28, 2023

Transmission Lines and Safety Considerations


A California-based electrical engineer, Dianoush Emami has significant experience designing power plants. Dianoush Emami has set up high-voltage transmission and electrical distribution systems that provide a consistent, safe energy source.

Transmission lines carry energy in large quantities from generating stations to substations, which can be distributed to individual businesses and households. The design and capacity of such lines vary widely, ranging from 44,000 volts to more than 750,000 volts.

Because of the high load capacity and extremely high voltage, transmission lines do not have an insulating sheath, as with the smaller loads involved with electrical lines and poles from substations. Instead, the air around the lines acts as an insulator, making it critical that nothing comes close to them, such as a tree branch, that might cause serious fire and outage. Because of the high voltages, a tree does not even need to touch the line for an electric arc to occur.

For this reason, all transmission lines are set up with right-of-ways that prevent vegetation from being planted in the vicinity. In addition, this cleared area enables personnel to access lines for inspections, repair, and maintenance.

Wednesday, February 15, 2023

Basic Types of Underground Transmission Lines

 Based in Southern California, Dianoush Emami oversees complex electrical engineering projects that enable power plants to function at capacity reliably. Over the years, Dianoush Emami has managed electrical engineering projects involving the placement of high-voltage overhead and underground lines.

Underground transmission lines must overcome various technical challenges that make the cost per foot between four and seven times that of overhead lines. One major obstacle involves providing enough insulation that cables can be placed only inches from grounded material. In addition, the heat generated when operating electrical cables needs to be rapidly dissipated within a confined space. With overhead lines, engineers have the luxury of lines surrounded by insulating air and safely distant from each other.

Two basic underground transmission line configurations resolve these concerns. High-pressure fluid-or-gas-filled cables involve three high-voltage conductors encased within a steel pipe. Pressurized nitrogen or synthetic oil acts as an insulator, without itself conducting electricity, and prevents unwanted electrical discharges. The fluid, generally static and operating by conduction, also transfers heat from the conductors. Issues that can potentially arise include leaking oil that impacts groundwater and soil.

The other major option is a solid cable made of dielectric material, such as the XLPE cable, which has an aluminum or copper conductor and a semi-conducting shield at the core. Surrounding this core is cross-linked polyethylene insulation, with a metallic sheath and plastic jacket covering the entire cable. This effectively provides insulation and heat dissipation without fluid leakage risks.

Wednesday, February 1, 2023

SF6 Circuit Breakers for High Voltage

 After receiving his bachelor's degree in electrical engineering from the University of Southern California, Dianoush Emami has accumulated several professional certifications in the electrical engineering sector. With over three decades of experience in his field, Dianoush Emami’s particular areas of expertise include quality control, safety, and high-voltage transmission work.

High-voltage circuit breakers protect electrical circuits from hazardous spikes. One common type of high-voltage circuit breaker is the SF6 circuit breaker. SF6 circuit breakers use a gas called sulfur hexafluoride as their dielectric material. The circuit breaker cuts power when there is an overload or a short circuit, protecting electrical systems and assets.

The three major types of SF6 circuit breakers are the single interrupter SF6 CB (designed for 220 kV systems), the two interrupters SF6 CB (designed for 400 kV systems), and the three interrupters SF6 CB (designed for 715 kV systems).

Circuit breakers are a more efficient alternative to fuses. Contrary to fuses, designed to protect against dangerous current only once, circuit breakers can be reused. One disadvantage of SF6 circuit breakers is that the constituent gas (sulfur hexafluoride) is a greenhouse gas and can contribute to global warming when it escapes into the atmosphere through the leakage.