The CCS comprises circuits such as the set load management centre, pressure regulation circuit in front of the machine, boiler master controller, and turbine master controller. It coordinates the operations, speed, and accuracy of the boiler and turbine, steadily responding to the load instructions of the central coordinator or operator, enabling the unit to generate the necessary electricity.
The boiler regulation and control system comprises several sub-systems, and the sub-systems are inter-coordinated, ensuring the boiler’s safety and speed, steadily generating the required steam for the unit’s load instructions.
The central reheating unit generally has a bypass system. The bypass system is a protection and regulation system to adapt to the starting and stopping of the reheating unit and accident status. Depending on the capacity and type of bypass system, the roles of the system differ and so do the control circuits.
Major thermal power generators have many controlled objects with complicated control processes, and the manual control is 1-on-1, which makes the generator unable to adapt to safe and economical operating requirements. It adopts sequence control to improve the work efficiency of operators, prevent accidents from erroneous control, and reduce the labor intensity of the persons on duty.
The FSSS is a necessary monitoring system for large modern thermal power boilers. Regardless of whether the boiler is operating normally, started, or stopped, the system will constantly and closely monitor the large number of parameters and statuses of the combustion system, and constantly conduct logic analysis and computation, and issue action commands where necessary. It can use different types of locking equipment to cause the relevant components of the combustion equipment to complete the necessary operations or deal with averted incidents based on the predefined reasonable procedures, so as to ensure the safety of the boiler combustion system.
The configuration and scope of the ECS is divided into the unit ECS and public ECS. The generator’s generator-transformer unit and the monitoring of the auxiliary power system and the common parts of the auxiliary power are mainly achieved using the DCS system. The key switching control signals and alarm signals are connected to the DCS system via hardwiring.
The DEHCS is an important function-oriented sub-system in generatorcontrol. It can be used for hydraulic servo equipment such as combustion-resistant oil and turbine oil, altogether comprising the DEHCS.
There are currently a few dozen established FGD technologies in the whole world, mainly comprising the wet, dry, and semi-dry methods. The methods include the wet calcium method (limestone – gypsum method), which is currently the world’s most established technology with the highest track-record of industry usage, and most operationally stable desulfurisation process. The total capacity of the generators using such processes account for more than 85% of power plant desulfurisation installations.
The ACC is a complicated system that involves the condensate collection system, vacuum hydrophobic system, closed – circuit cooling water circulation system, desalted water system, and bypass system.
The supercritical pressure one-through boiler (SPOTB) does not have a steam drum, and requires the regulation quality of fuel-water ratio, wind-fuel ratio, and reduced temperature water to be relatively high. The SPOTB has small storage capacity with distributed characteristics, has poor variable load performance, and it is relatively difficult to maintain the steam pressure. The performance of the SPOTB set is extremely non-linear and the SPOTB unit is a multi-input and multi-output controlled object with strong coupling characteristics.
The energy engineering site of Guohua Hulunbeier is located at the Baorixile mine at Hulunbuir city in Inner Mongolia. In Phase I, 2 600MW SPOTBs were installed, and the HOLLiAS MACS system of HollySys was adopted for the DCS and DEH control system.
Boiler manufacturer: Harbin Boiler Factory Model number: HG-1913/25.4-HM15
Turbine manufacturer: Shanghai Turbine Factory Model number: NZK600-24.2/566/566
Thermal automation equipment: Made by HollySys Model number: HOLLiAS MACS DCS
I/O points of generator unit and common system:
Another 594 points were communicated to DCS via front-end acquisition.
3 domains have been set for the two sets and common system for this project. The domains are connected using fiberoptic cables to facilitate inter-domain communication. The user can use voice commands to monitor and operate equipment in different domains. The DEH system and DCS system is altogether managed from an engineer station. The air cooling system can be connected to the system control network via remote station. The data I/O service and historical trend services are set in different servers, which not only improve real-time processing capability, but also reduce load ratio, making it much more reliable. The system structure is as shown in the following diagram.
The DCS system uses the boiler-tracking one-through boiler coordinated control strategy, feedwater control strategy for mid-point enthalpy control, and a lignite-targeted combustion regulation strategy. A complete frost protection and heating program control is designed for air cooling sets operating in cold areas at high altitudes. A unique design was adopted for the DEH system’s primary frequency-modulation circuit, main valve, and regulating valve switching circuit, ensuring more stable control for upgrading and failure load shedding.
The Guohua Hulunbeier power plant (2*600MW) uses the HollySys’ HOLLiAS MACS system to realise the integrated control of the machines and boilers. When implementing the power plant project, Beijing Guohua Electric Power Co., Ltd arranged for domestic power system experts to conduct full tests and reviews of the system’s performance, functions, and control program. During the trial run of the machine units, the system’s test indicators and test parameters reached levels that were high by industry standards.
On 1 Dec 2010, two machines commenced commercial operations after a 168-hour trial run.