Rockwell Products Solutions for Power System Control Systems

background:
The Chinese government is gradually liberalizing its management of the energy industry, which has forced power plants to seek new and more effective ways to generate electricity and distribute electricity. Policy makers also recognize that to win the market in the future, we must increase efficiency and reduce production costs.
However, at the same time as there is a huge potential for transformation, the ultra-low cost and the load demand that increases at an annual rate of 8% also pose a great challenge to the transformation.
Fortunately, industry decision-makers clearly recognize the fierce competition in the future and are trying to implement the automation of power transformation. One example is the transformation of Shandong Huangdao Power Plant.
Huangdao Power Plant, located in Qingdao, is one of the major power suppliers in Shandong Province with a high degree of industrialization. The plant put forward slogans to continuously carry out technical transformation, including meeting the ISO requirements of the various quality standards. At present, the plant is implementing a series of modern technological transformations and has received noticeable results.
challenge:
Engineers at Shandong Huangdao Power Plant have recently embarked on a modernization plan to reduce energy consumption and improve the process control of negative pressure fan systems. The negative pressure ventilation system controls the rate of air flow into the furnace to accelerate or suppress the burning of coal in the boiler.
Problems with the original system: The fan system of the original system connected to eight 800-kilowatt motors is continuously operated regardless of the power load requirement. Burning speed is also controlled manually by opening or closing the damper on each boiler. When the power demand is small, these devices will bypass the air entering the combustion process or remain open when the demand increases.
The result of the problem with the original system is that the motor continues to run at full speed, resulting in excessive energy consumption. The windshield system also cannot provide accurate flow rate control, resulting in sub-optimization of combustion control and significant waste.
The annual cost of the original system was staggering, but the power plant has never been systematically counted, and production managers can only roughly estimate the resulting economic impact.
In order to solve this problem, the management of the power plant began to look for suppliers that have extensive experience and can provide comprehensive customer support to provide the best equipment modification solutions for power plants. They chose Rockwell Automation China.
solution:
In this renovation project, Huangdao Power Plant also selected Sihai Automation Engineering Co., a subsidiary of his sister company, China's largest power holding company SEPCO, as his partner to provide engineering design for the project transformation together with Rockwell Automation. and service.
Engineers from both companies agreed on the use of medium-voltage variable frequency drives to control motor speed and operation. With this solution, the motor and the boiler fan can be operated as required, that is, the motor can most effectively bring the boiler fan at the lowest speed according to the actual load requirement to achieve the best combustion effect. Because it is not necessary to control the airflow, the damper door can also be cancelled. In addition, it is possible to convert the motor from "hard start" and "hard stop" to soft start and soft shut down so that inrush current can be minimized without compromising circuit and motor performance. Finally, more precise control of the coal used for combustion can be achieved, thereby reducing waste. In addition, the quick installation feature of the medium-pressure drive scheme also minimizes downtime.
Rockwell Automation’s mid-voltage inverter PowerFlex7000 is at the heart of this fully automated solution. This 18-pulse converter is regeneratively decelerated, allowing motor braking to be fed back to the plant without additional hardware and software. This is ideal for pumps, fans, and blowers that often require rapid deceleration due to high inertial loads.
The output voltage and output current are also very good sine waves, which means that it can directly drive an ordinary motor without resorting to power reduction or filter addition, and the operating temperature of the motor will not rise significantly. At the same time, since the PowerFlex is a 6kV inverter device, it does not need to add as many expensive, simultaneous fail-prone buck and boost hardware devices as the 3kV inverter device.
Cosmopolitan provides its associated engineering design and integration services, as well as the 18-pulse isolation transformer required for local procurement. Rockwell Automation's Global Manufacturing Solutions Group also provides full startup and field trial services to ensure system integrity and performance.
Achievements:
Today, the Huangdao Power Plant uses electricity annually to reduce electricity by 30 million kWh, saving US$1.2 million in capital.
In fact, the cost savings have accelerated the return on investment of the Huangdao Power Plant. The plant has recovered all of its investment in just two years. The rapid return on investment is a significant feature of medium-voltage inverter solutions.
The scheme is based on the original motor and motor control circuit breakers of Huangdao Power Plant. In addition, the new control equipment is also transformed within the existing equipment room and circuit configuration, which speeds up the implementation process and saves costs for future engineering designs and hardware.
“Although many companies claim to be able to provide customers with customized medium-voltage solutions, we believe that only Rockwell Automation and Cosmopolitan have done the best,” said Li Huang, director of Shandong Huangdao Power Plant.
Jiying said, "We have decided to continue working with them to continue adopting their solutions in future projects."
The success of this transformation is inseparable from the long-term cooperation between Rockwell Automation and China Four Seas in China and throughout the Asia-Pacific region to provide medium-voltage inverter solutions.

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