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A bunch of tangled wires power the shops at Crawford Market in Mumbai. Photo: Eitan Iron
The screams of children while playing cut through the hustle and bustle of cars and motorized rickshaws driving in a high-rise apartment complex in Khar, a narrow, tree-lined alley in central and western Mumbai, the city formerly known as Mumbai. This pulsating island with a population of 18.2 million is the most populous city in India and is the economic engine that propels the country into the ranks of developed countries.
Noisy traffic noises, construction noises and crows' cries are filtered into my spacious one-bedroom apartment. The hustle and bustle of the street merges with the sound of modern electrical conveniences: the humming refrigerator, the humming The ceiling fan, the buzzing water heater, the buzzing air conditioner and the roaring espresso machine.
I turned up the volume on the cable TV and listened to the BBC anchor reporting the headlines of the day. Three new luxury apartment buildings are rising from where the slums are. Many of these developments are surrounded by tarp-covered shacks and crumbling low-rise concrete boxes that hold half of the city’s residents, making Mumbai one of the largest slum populations in the world. In mid-2006, the former slum dwellers of this particular neighborhood-many of whom provided basic services to surrounding middle-class families, such as garbage removal, newspaper delivery, bread, fruits and vegetables-were moved into an unfinished house Area. The apartment complex is placed side by side with the gorgeous new apartments.
The window frames of the recently relocated slum residents may not have glass, but they have lights and TVs. They are by no means a unique privilege among the poor in Mumbai, and even for the less affluent residents of the city, the cost of electricity is not generally unaffordable. At only 2 rupees (less than 5 cents) per kilowatt hour, Mumbai people are not shy about using electricity. At dusk, Dharavi, a few kilometers to the east and south, is the largest slum in Asia, with about 1 million residents. Electric lights are lit in the narrow studio apartments and the TV flashes blue through the open windows.
Readily available, affordable and reliable electricity is the foundation of any modern city. With it, you will have the iconic bright lights of Times Square in New York City and the psychedelic neon carnival in Shibuya, Tokyo. Without it, you will see the suffocating haze of diesel fumes from Lagos and thousands of generators, a dirty and expensive alternative to grid-connected electricity. Tourists often compare Mumbai with Lagos rather than New York City. One important reason is that Mumbai enjoys reliable electricity, and it has always been since the first hydroelectric power station of the Mumbai-based Tata Electric Power Company began delivering electricity to the city’s textile mills in 1914.
This seems to be a cruel joke. Just as India is preparing to become an economic superpower, utility companies in the country’s model cities have launched their own public service campaigns, urging Mumbai Gals to save energy or face widespread planned power outages this summer. For the first time ever. In February this year, a power outage occurred in the northern half of the city, further illustrating the dangerous situation in Mumbai.
"The load is rising much faster than anyone realizes," said Gerry F. Grove-White, Tata's executive director and chief operating officer. "I looked at my apartment and every tower crane I saw, and I saw the increased load," he said in the loud harsh sound of the office air conditioner. "And power generation investment has not kept up. We passed by last year. As soon as this summer arrives, the jury will come out."
In Mumbai, everyone has access to electricity—up to 95% of the population according to utilities—every day of the year, 24 hours a day. "The reliability of electricity in Mumbai is very good. It is no exaggeration to say that most people do not prepare flashlights or even candles for emergency use," said Dilip A. Sathe, general manager of Tata Corporation.
No one else in India is so lucky. In January last year, the country's total peak power demand exceeded the supply by 15,540 megawatts. Planned load shedding is common, especially in rural areas, although cities, including the megacities of Delhi and Kolkata, are not immune: utility companies cut off electricity for customers for several hours at a time to balance load and generation capacity, thereby maintaining generators Operating between 48.5 and 50 Hz, the frequency specification of the Indian power system.
Five main power grids-located in the north, east, northeast, west and south-serve India. With the exception of the Southern Power Grid, all other power grids have a total generation capacity of more than 100,000 MW and are in a synchronous relationship, which means that they are connected to each other and share a common system frequency. Maharashtra, with Mumbai as the capital, is part of the Western Power Grid, which also includes Gujarat, Madhya Pradesh, Chattisgarh and Goa, covering an area of 11 million square kilometers and an installed capacity of approximately 47,000 MW.
Since Mumbai is connected to the Western Power Grid and receives part of its power from the Maharashtra State Transmission Company to meet peak demand, the load in the city directly affects the situation in other parts of the state. Mumbai’s peak load of approximately 2,600 MW now greatly exceeds the local power generation capacity of only 2,277 MW. Tata provides 1,777 MW of electricity to its direct customers, including commuter railways and heavy industry, with a peak load of approximately 500 MW. Tata also powers the Brihanmumbai Electric Supply & Transport Undertaking (BEST), a public company that operates the city’s bus system and distributes electricity to southern Mumbai. The peak load of BEST customers is approximately 800 MW. Reliance Energy, another major utility company in Mumbai, also purchased electricity from Tata to supplement its 500 MW of power generation and meet its customers' peak load of 1,300 MW. In order to make up for the shortfall, Tata often purchases electricity from Maharashtra, and the company pays US$94 million in standby fees each year on the basis of the actual cost of imported electricity.
The peak demand in Maharashtra is approximately 17,000 MW, which exceeds the power generation capacity by approximately 5,000 MW. This means that parts of Maharashtra are carrying out planned load reductions every day, and many rural areas there have only 10 hours of electricity supply. This poverty is a fact in the daily lives of most Indians outside Mumbai, just like the monsoon.
Improving the availability, reliability, and quality of electricity is a long-term goal, which can only be achieved by adding tens of thousands of megawatts of power generation. In the short term, managers and engineers from the Mumbai Electric Power Company Tata and Reliance, as well as officials from the Maharashtra State Electricity Regulatory Commission, are doing their best to avoid the planned load shedding and avoid possible local economic losses. Catastrophic power outage of billions of rupees.
Due to the loss of the generator or the main transmission line, when the load far exceeds the power generation, a power outage will occur, and the frequency will drop to 47.5 Hz. At that time, the generator will automatically trip and then lose power. For example, on February 25, the power grid in western India failed, and residents of Maharashtra were out of power for several hours.
But as usual, Mumbai mostly survived. Both Tata and Reliance have invoked the "Island" plan, in which they separate the city from the national grid and supply power to customers from their own local factories until the larger grid is restored. Tata was first deployed in the late 1960s, and separation only occurred when system integrity could not be maintained despite automatic emergency load shedding. The island does not need to be controlled by a central computer. Instead, the reverse power and underfrequency relays sense that the system frequency has dropped to 47.6 Hz and independently trip the circuit breakers on the 6 power lines connecting Tata and Reliance to the regional grid.
In most cases, Tata and the Reliance system live together as an island, but occasionally Reliance will separate into a separate grid, as happened in February this year. On that day, Tata’s power generation was very low due to the outage of a 500-megawatt coal-fired generator and a 150-megawatt gas turbine. According to Reliance's chief consultant K. Rajamani, the utility company has been importing electricity from Tata through a tie line with a capacity of 30 MW. On the same day, a 400-kilowatt transmission line near Mumbai experienced a problem, causing the grid to become unstable.
When the system frequency dropped to 47.6 Hz, Tata and Reliance were separated from the sinking western power grid. Under normal conditions, power flows from Tata to Reliance through interconnected tie lines. But on February 25, problems with the Western Power Grid, coupled with insufficient power generation from the Tata system, caused huge power fluctuations and reversed the normal power flow from Tata to Reliance.
The reverse power condition deceived the load shedding logic in Reliance's supervisory control and data acquisition (SCADA) system, which is based on the power input from the tower. As a result, the SCADA system did not initiate automatic load shedding, and the Reliance generator provided power to the Tata load. This resulted in a sharp drop in frequency, which caused Reliance's 500 MW plant in Dahanu to trip generators and shut off electricity to approximately 1.7 million customers for 1 to 4 hours. Once Reliance's system started to fail, Tata became an island in an island. Although the power generation capacity is below normal, Tata managed to keep the lights on the southern part of the city served by its customer BEST. This is the 14th successful island since the last city-wide power outage in 1997.
Mumbai’s dramatic increase in load over the past five years-an average of 5% per year-has strained the existing power system to its limit. Only a small part of the increase can be attributed to the possible influx of 1,000 migrants every day, most of whom are destined to sleep on the sidewalk or seek shelter in slums. Some of the recent demand comes from new air conditioners and washing machines. These purchases benefited from the strong national economy, which grew at a rate of 8.5% last year. Then came the construction boom. Much like Manhattan, Mumbai can only accommodate an expanding and increasingly wealthy population through vertical development. Tower cranes can be seen everywhere helping buildings rise into the skyline. In addition, the large-scale conversion of an old textile factory of 243 hectares in the city center into commercial and residential spaces is creating a dazzling, fully air-conditioned shopping mall comparable to consumer temples in the suburbs of the United States. Together, it is no wonder that power companies that have not built a new power plant in ten years are scrambling to keep lighting.
How did it get to this point? In short, India's power business has proven to be a financial minefield. Take the 2,184 MW Dabhol Power Plant near Mumbai as an example. If it is fully operational, this facility may have eliminated nearly half of the power generation capacity gap in Maharashtra. Currently, only the first phase of 740 MW has been completed, and it only operated for a short time before the plant was closed in 2000. In May last year, Ratnagiri Gas and Power, a company jointly owned by seven companies including National Thermal Power Corporation, headquartered in New Delhi’s Corp. and the Maharashtra State Electricity Commission took over the plant, which used naphtha. Oil is the raw material, and naphtha is the product of the crude oil refining process. However, due to oil prices hitting record highs, Ratnagiri has not yet resumed daily operations because of the high cost of electricity at the naphtha plant.
Mumbai’s power company has also been burnt down when building new power plants in the past. Since until recently, India did not have a unified national grid or regulatory mechanism to facilitate electricity trading, it was unable to sell excess electricity. This inability has brought economic disaster to Dahanu's 500 MW coal-fired power plant, which was commissioned by the Mumbai-based Brihanmumbai Suburban Electric Supply (BSES) during the brief economic boom in the mid-1990s. The plant was built in anticipation of an increase in demand, and it was only recently realized. At the same time, expenses related to Dahanu paralyzed BSES, and in 2003 Reliance took over the plant and the rest of BSES's Mumbai business.
Ten years after Dahanu’s collapse, India is a different place. The people here are optimistic about their economic future, which is emphasized by the thousands of Indians who have returned from abroad in search of wealth. "It is generally believed that the economic surge we are seeing this time will continue," Grove-White said. Thanks to the mature electricity trading mechanism and the new regulatory environment facilitated by the 2003 Electricity Act, Tata officials believe that they can get considerable returns from their investment in the new plant. "We will have to take a deep breath and say, we want to invest," Grove-White added. "We know what we need to do, and we will eventually sell these products."
In fact, as the private sector injects funds, several new factories are under construction or are about to be constructed. A 250 MW coal-fired unit is scheduled to go online at Tata’s Trombay complex in March 2008, and another 250 MW unit is scheduled to follow up in 2009. The central government of India is also stepping up its pace, awarding contracts for four so-called super-large units each with a 4000 MW coal-fired power plant. They will be built by a number of Indian companies including Tata.
Clinton J. Andrews of Rutgers University in New Brunswick, New Jersey, said that initiatives to create more power generation in response to increasing demand underline the fundamental dynamics of managing global energy planning. Then you won’t waste any of it. Engineers prefer to build it before demand, because then you always have enough capacity,” he said. “In the power industry, the influence of engineers is declining, and economic and business perspectives are increasing. . This means that wherever we see the power system operating closer to the margin, including the United States, and of course in Mumbai, they are facing the additional complexity of insufficient capital, so they cannot build the required number of power plants. "
In Mumbai, there is a delicate dance between the city’s electricity production and distribution company and the state regulator. The regulator mainly acts as a protector of consumer rights and always wants to keep electricity prices as low as possible. But the current situation forced the regulator to take action in April, when the Maharashtra Electricity Regulatory Commission approved an increase in the electricity bills of Mumbai customers to 27% of residential consumers and 75% of commercial and industrial users. Andrews, director of the urban planning and policy development program at the EJ Bloustein School of Planning and Public Policy at Rutgers University, agrees that raising prices may help Mumbai's long- and short-term conditions.
"For a city like Mumbai, part of the solution is usually to start charging enough electricity," Andrew pointed out. "There are two things. First, it creates a revenue stream that you can use to borrow money to build power plants. Second, it suppresses demand, especially if you can do timing measurement, which encourages people to perform peak shifts. And minus peaks."
In fact, according to Rangan Banerjee, a professor of energy systems engineering at the Indian Institute of Technology in Mumbai, Maharashtra has recently introduced so-called daily billing for industrial customers in India. There are four time periods under the new tariff schedule: the morning peak from 6 am to 11 am; the evening peak from 6 pm to 11 pm; and two off-peak troughs where demand drops, from 11 am to 6 pm. From 11pm to 6am. The idea is to allow heavy industry users to shift load-intensive operations to off-peak hours when costs are lower.
Banerjee said it was a good idea. But so far, this plan has failed. "When tariffs were introduced, prices were also rationalized," he explained. “In the past, industry subsidized commercial customers and agriculture by paying the highest tariffs. When we switched from a flat tariff to a time-sharing tariff, the industry’s bills were reduced. Therefore, they have not yet realized their motivation to leave work.”
Despite the slow adoption rate, Banerjee firmly believes that this demand-side management will eventually win. "Load management and energy efficiency are more convenient options than reducing the load, and much cheaper than building a new plant. But demand-side management [DSM] will not completely offset any power plants. We will have new power plants and DSM because No matter what we build, we will still have shortages."
The power company in Mumbai knows that the power shortage will become severe in just a few months. Throughout the spring, Tata, Reliance, and BEST launched a public awareness campaign on TV, radio, billboards and flyers. The goal is to enable citizens to save 20% of their energy use instead of incandescent light bulbs by turning off electrical equipment when they are not needed, running large appliances such as washing machines during off-peak hours, minimizing the use of air conditioners during peak hours, and using compact fluorescent lamps. Turn off the power to the billboard during peak periods. (Some people want to know whether those billboards that promote energy conservation will also be dimmed.)
The message from the power company is clear: In order to survive the tropical summer without significant power outages or blackouts, Mumbai people will have to sacrifice some of the convenience they have enjoyed over the past few years. If they do not, the noise of the TV, washing machine and espresso machine may be replaced by the sound of matches in the dark.
To view all of Spectrum’s special reports on megacities, including online extra shows and exclusive audio and video reports, please visit /moremegacity.
Harry Goldstein is the editorial director of IEEE Spectrum Digital Assets.
They cover key concepts, implementations and forecasts
In order to continue operations during the pandemic-related shutdowns, organizations around the world have undergone digital transformation. Examples include the use of remote technology to collaborate with employees and customers, and the use of automation to improve the customer experience. Now, as the world tries to determine the new normal, many companies are expanding their use of digital transformation as a growth tool.
A recent McKinsey survey on digital transformation during the COVID-19 pandemic revealed that after more consumers switched to online ordering, organizations accelerated the digitalization of customers and supply chain operations. The survey found that companies with reduced revenues in the past few years tended to lag behind in the use of digital technology.
How do you ensure that your organization is prepared for the digital society? To help, the IEEE Educational Campaign created a five-course course, Digital Transformation: Towards a Digital Society.
"Digital transformation is permeating every industry and will be everywhere," said Roberto Saracco, course creator, senior member of IEEE, and head of the industry advisory committee of the IEEE Future Directions Committee. "It is important for organizations to understand how the digitalization of their business will affect their consumers and operations."
Understand the key concepts. Technology professionals can understand the concept of the technology ecosystem while also understanding how digital transformation can change organizations and reshape market niches.
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To learn more about how digital transformation affects your company, sign up for "The Benefits of Organizing Digital Transformation", a free virtual event that will take place on November 16th at noon New York time. It is sponsored by IEEE Educational Events and proposed by Saracco. Two hours after the on-site event, the meeting will be provided on demand.
This drone only needs a motor and flexible wings
It turns out that making a flying robot does not require a lot of hardware. Flying robots are often over-engineered, with ridiculous top components, such as two complete wings or four independent motors that are obviously ridiculous. Maybe this kind of thing is suitable for those who have too much money and don’t know what to do, but for anyone trying to keep a reasonable budget, making a flying robot actually only requires an airfoil plus a fixed-pitch propeller. If you Make the wings flexible, and you can even fold the whole thing into a flying robotic Swiss roll.
This type of drone is called a single-axis aircraft, and its design is usually based on samara seeds, which are single-wing seed pods that spin down from a maple tree. The ability to rotate slows down the speed at which the seeds descend to the ground, allowing them to spread farther from the tree. This is an inherently stable design, which means that it will spin on its own and proceed in a stable and predictable manner, which is a great feature for drones-if everything is completely gone, it Only gently rotate to the default login.
The single axis aircraft we see here called F-SAM comes from Singapore University of Technology and Design. We have written about some of their flying robots in the past, including this deformable hovering rotorcraft. F-SAM stands for foldable single-drive single-axis aircraft. As you might expect, it is a single-axis aircraft that can be folded and controlled with only one driver.
In terms of hardware, there may not be much progress here, but this is part of the charm of this design. One actuator provides complete directional control: increasing the throttle will increase the aircraft's RPM, allowing it to gain altitude, which is very simple. Directional control is more tricky, but not more tricky. When the plane is pointing in the direction you want it to go, you need to pulse the motor repeatedly at a certain point during the rotation of the plane. F-SAM operates in a motion capture environment in the video to explore its potential for precision and autonomy, but it is not limited to this environment and does not require external sensors for control.
Although the F-SAM control panel is custom-designed and the wings require some manufacturing, the rest of the components are cheap and readily available. The total weight of F-SAM is only 69g, of which nearly 40% are batteries, and the flight time is about 16 minutes. If you look closely, you will also see a small carbon fiber leg, which can keep the support above the ground, so as to achieve ground take-off behavior without touching the ground.
You can find the complete F-SAM paper here, but we also asked the author some additional questions.
IEEE Spectrum: It looks like you have explored different materials and material combinations for flexible wing structures. Why do you end up with this mixture of balsa wood and plastic?
Shane Kyi Hla Win: The wing structure of a single-axis aircraft needs to be rigid in order to be controllable in flight. Although uniaxial aircraft can fly with more flexible materials that we have tested (such as flexible plastic or polyimide flexible materials), they allow the wings to twist freely in flight, thereby reducing the loop control effect of the motor. The balsa wood laminated with plastic provides sufficient rigidity for effective control while allowing folding and folding in a predetermined triangle.
Can F-SAM fly outdoors? What does it take to fly outside of a motion capture environment?
Yes, it can fly outdoors. It is passive and stable, so its flight does not require closed-loop control. When indoors, the motion capture environment provides absolute positions for station keeping and waypoint flight. For outdoor flight, the electronic compass provides relative heading for basic loop control. We are developing a prototype with integrated GPS for outdoor autonomous flight.
Can you add cameras or other sensors to F-SAM?
It is possible to add a camera (we have already done this before), but due to its rotating nature, the captured image may be blurred. 360 cameras are getting lighter and smaller, we may try to install one on F-SAM or other single axis aircraft we own. Other possible sensors include LiDAR sensors or ToF sensors. With LiDAR, the platform has an advantage because it already rotates at a known RPM. Traditional LiDAR systems require dedicated actuators to generate rotational motion. As a rotating platform, F-SAM already has natural rotation dynamics, which makes LiDAR integration lighter and more efficient.
Your paper says "In the future, we may study the possibility of launching F-SAM directly from the container without manual intervention." Can you describe how this will happen?
Currently, F-SAM can be folded into a compact form and stored in a container. However, it still requires humans to unfold it and launch it manually or place it on the floor to fly away. In the future, we envision putting F-SAM in a container that has a mechanism to eject the folding unit into the air (for example, pressurized gas). Thanks to the use of elastic materials, the unit can be unfolded immediately. The motor can start to rotate, making the wings straighten due to centrifugal force.
Do you think F-SAM will become a good consumer drone?
F-SAM may be a good toy, but if the target is traditional aerial photography or videography, it may not be a good substitute for quadcopters. However, it can become a strong competitor for one-time GPS-guided reconnaissance missions. Since it uses only one actuator for flight, it can be manufactured relatively cheaply. It is also very quiet during flight and is easy to camouflage after landing. Various light sensors can be integrated into the platform for different types of tasks, such as climate monitoring. F-SAM units can be deployed from the air because they can also rotate automatically during descent, and can also fly at certain times for long-term weather data collection in the air.
What are you going to do next?
We have some exciting projects at hand, most of which focus on the theme of "Doing more with less." This means that our project aims to achieve multiple missions and flight modes while using as few actuators as possible. Like F-SAM, which uses only one actuator to achieve controlled flight, another project we are working on is a fully-rotating version called the Samara Spin Wing (SAW). The platform was published on IEEE Transactions on Robotics earlier this year, and two flight modes (rotation and diving) can be realized with only one actuator. It is very suitable for deploying disposable sensors to remote areas. For example, we can use the platform to deploy sensors for forest monitoring or wildfire warning systems. The sensor can land on the tree canopy, and once landed, the wing provides the necessary area for capturing solar energy for continuous operation for several years. Another interesting scene is the use of an automatic rotating platform to guide the radiosonde back to the collection point after it has completed its upward journey. Currently, many radiosondes are launched with hydrogen balloons from weather stations around the world (only over 20,000 from Australia each year). Once the balloon reaches a high altitude and explodes, the sensor will fall back to the earth without any effort to retrieve these sensor. By directing these sensors back to the collection point, millions of dollars can be saved every year—and [it helps] protect the environment by reducing pollution.
Transform more than 55,000 substations into independent micro data centers to solve the most pressing power distribution, security, and cost challenges that plague the U.S. power grid. Learn how virtualization provides a total solution to modernize and expand the power grid, with the capacity, protection, and reliability needed to keep power flowing smoothly.