The Smart Grid- Solution To Transmission Line Congestion

Most of us take it for granted that we just hit a switch and the light comes up; we turn to the blender when we want to mash that pineapple to make juice without a thought about how the electricity came to be that reliable. Look at that emergency section of the hospital or the operating theatre where several machines including life support are keeping the patients alive. I often think about electricity, especially when using elevators, what if there is an outage trapping one inside? But then the electrical power system network is so robust that it will not allow that to happen.

^{Wikipedia: A Smart Grid and its functions}


Power outages have been a major problem in Nigeria where virtually everyone has a hand in his power generation. When you put into consideration that this generation is not renewable or cheaper than the conventional method of generation (hydro, steam, nuclear, gas etc.), you will realise what the individual is losing each hour with regards to power generation. The cost per kilowatt hour of power generated from these generators are high because of the high cost of their fuel which is majorly petrol and diesel. This kind of generators is not ideal for conventional power generation. Ideally, petrol and diesel engine generators are used in an emergency situation or in remote locations where the National grid has not gotten to.

When you look around, you will notice that telecommunication has evolved over the years and the improved impact is undeniable. One cannot say the same about the National grid especially the distribution system. People often make the mistake of believing that the problem is purely generation without knowing that distribution is also part of the vehicle that will convey the power to its destination (consumer terminal). Providing the goods (power) is not enough, there must be a vehicle (efficient transmission and distribution network) to transport it to where it would be utilised.

If we continuously overload a vehicle, it is only a matter of time before the body and engine will start showing signs of stress and if the overload persists, disintegration becomes imminent, and that is the same case with the transmission and distribution network. There is need to take off pressure from the grid system with the help of evolving smart energy devices and systems, and the result would be an improvement in grid reliability and security while promoting the growth of cleaner power generation.

Our transmission and distribution system needs an overhaul because it is weak, ageing, cannot accommodate renewables and mostly inefficient. Smart grid concept can make a whole lot of difference and can go a long way to eliminate the problems mentioned above.


What makes a grid smart?


The concept of a smart grid emerges from the integration of the power systems view of the electricity grid with its corresponding information systems view. There would be widespread use of information network to enhance the operation of the electricity grid. This integration of power infrastructure with an information infrastructure would affect the consumption pattern of the consumers. The communication infrastructure will allow the consumer to communicate with the utility company. Conventional grid only allows one-way communication which is usually from the utility to the consumer making the consumer inactive.



Flickr CC: A Smart Grid Solution

Communication is important because the consumer will know when there is low power demand on the power system. The utility company can add an incentive by varying their cost depending on the demand on the station. Those customers that may want to buy during the period of light load will get a discount while those that buy during peak period can be charged higher to discourage consumption. With the efficiency, connectivity, savings in cost made possible through Information Technology, the grid will be utilized optimally without even any need for redundant stations (generators primed to be called upon in the event of peak demand or emergency).

Some of the characteristics of smart grid include:

• Active participation of customers and allowing the consumer choose when to buy power based on price signal.
• The smart grid should be able to accommodate both conventional and renewables (distributed generation) and all the storage option available. The grid should be robust enough as to integrate into the centralised system the fluctuating and sometimes intermittent nature of renewables.
• Newmarket like the transfer of power to and from the grid by such product as the plug-in hybrid electric vehicle should be encouraged and accommodated by the grid.
• A smart grid should be able to segregate and furnish each consumer the quality of power tailored to his taste and need.
• Optimization of assets with increased efficiency. The use of Supervisory Control and Data Acquisition (SCADA) should lend more fidelity to the transmission and distribution network. The remote terminal units (RTU) in the field should be able to monitor the assets whether at the consumer end or the utility end. With the optimal utilisation of assets, invariably, higher efficiency will be achieved.
• It should be able to perform contingency analysis, find out likely fault, forestall it and respond to system disturbances. In the event of an actual fault, the system should be able to self-heal thereby increasing the reliability index.
• It should be able to operate resiliently to attacks, be it human-made or natural disaster without waiting for repair crew or linesmen to trace the fault and or initiate switching.

How will the smart grid operate?


Assuming there is an increase in the number of houses leading to an increase in load demand on the power station in a specific part of the community scenario.
Let us say that the new development adds 500 new homes the local utility. Then it, therefore, means that they can either build a new substation or create a 21st-century power network rich in information technology and telecommunications bandwidth. If the utility already has a fibre optic network that is not entirely engaged, it, therefore, means the decision will swing to the advanced technology route. Customers will be encouraged to assist the grid by adding some incentive like paying back the customer a certain amount by purchasing power at a period of low demand or by using gadgets and appliances that has a power factor close to unity.



Wikipedia: Smart Grid Function Diagram

The rebate to the customer is because he is demanding power when there is less pressure on the power system as opposed to when the demand on the power system is high. The electric network facility will experience overload if every customer demands his bloc of power at the same time. If the overload is sustained, it imposes stress on the facility which if the utility wants to accommodate will make them incur higher cost regarding network upgrade.

The provision of smart meters to the customers will ensure that they receive price signal while at the same time report moment-to-moment power use to the utility. Residential customers are provided rebates for buying smart appliances that can sense the best time to be connected to the grid in response to grid needs and signals.

These technologies afford customers the opportunity to take part in a voluntary demand side management response program, which gives them credits on their bills for reducing power use in peak demand periods or when the grid is under stress. Smart appliances accomplish this task this automatically without waiting for any input from the customer, though it is possible to disengage the system when they deserve control of their devices over the Internet. Since peak demand is lower, there are savings in investment in poles, transmission lines when the power is generated far away from the load centres.

Smart grid entails automation of power distribution system, local substations and other power infrastructure are fitted with remote terminal units. By so doing, tasks that were previously performed manually on-site can now be remotely controlled. This remote control allows the more optimum use of infrastructure. For example, we know that most industrial areas utilize a higher power during the day while most residential regions demand more power during the night because that is when they are mostly at home.

As a result, transformers in such residential areas will be underutilised during the day when everyone is at work while the transformer in the industrial sector will be underutilised during the night.But with smart grid automation, it will only take one automated transformer to serve both areas. During the day it transfers capacity to the factory, while at night it shifts it over to residences. Automation also helps to reduce downtime in case of a blackout and allows the system to delivers better voltage control.

There would be reduced line losses by making local generation more financially rewarding; smart energy technology increases significant gain in overall efficiency of the line by reducing transmission losses and congestion. Up to nine percent of electricity leaks from wires between generation and consumption. Distributed generation clamps down the figure to around two percent which is achievable when distributed generators are offline. Other smart energy technologies installed within grid infrastructure, such as voltage control, also have been known to reduce line losses.

Another move to increase local power generation is installing solar photovoltaic modules at homes and businesses to handle dry season peak loads. These local power sources help to reduce the urgency to expand the transmission capacity within the vicinity. The avoidance of power line network expense makes money available to engage in the purchase and installation of solar modules and other local generation methods (wind) which is cleaner and more environmentally friendly.

REFERENCES

1. Smart Grid Overview
2. Smart Grid Technology
3. Powering up the Smart Grid