Baldor - Motors, Drives & Generators

SINOHYDRO (China) moves 60M tons of gravel over 31km, 5 light conveyor system with Baldor CST™ Drives…

In the remote south-western province of Yunnan, some 2000km from Beijing and Shanghai, SINOHYDRO is contructing another vitally important piece of China’s renewable energy program. The Xiang Jia Ba dam and hydropower scheme is the nation’s third largest hydropower system and another major step forward in China’s sustainable energy and water resource management strategies.

To build this dam, SINOHYDRO chose Baldor’s CST (Controlled Start Transmission) as the best drives solution, installing 13 Baldor CST Drives and 2 CSB Braking units to deliver some 60 million tons of gravel over 31 kilometers on 5 conveyor flights, laid through 29 kilometers of tunnels.

When completed in 2015, the 30.7 billion kWh/ year of electricity that will be generated by the Xiang Jia Ba hydro scheme will replace the equivalent of burning 14 million tons of coal per year. The follow-on effect of this renewable energy is also a significant reduction in emissions, equivalent to 25 million tons/y of carbon dioxide, 170,000 tons/y of nitrogen dioxide and 300,000 tons/y of sulfur dioxide.

Baldor 1120K CST Drive

Xiang Jia Ba will begin generating power in 2012 and the power will be transported by high tension power lines to China’s central and eastern provinces. In addition to providing power, the 900+ million cubic meter reservoir on the Jin Sha Jiang River will help cities like Chongqing, Zhouzhou, Yibin and Shuifu (where the dam is located) and others to achieve national flood prevention standards. It will also provide water to irrigate approximately 3.7 million Mu (250,000 hectares) of land in 14 downstream regions.

BALDOR CST™… A TRUSTED NAME AROUND THE WORLD
SINOHYDRO Corporation is the largest and most successful Chinese construction company in the field of hydraulic and hydropower engineering, and is managed internationally as a state-owned enterprise. It is ranked as one of the top technology companies in the world in terms of hydropower construction experience, having completed 70% of all hydro projects in China including the world renowned Three Gorges Project. China’s total installed hydropower generation capacity has now reached 100,000 MW.

The scale, rugged topography and shear isolation of the SINOHYDRO Xiang Jia Ba project created numerous technological and logistical hurdles. Designing, developing, manufacturing, installing and supporting a reliable conveyor system on this scale presented an enormous challenge. A challenge that could only be trusted to a proven supplier with the required depth of engineering knowledge, extensive project experience within China and a proven record. Baldor and its proven CST technology were again chosen for this task.

One of the Xiang Jia Ba conveyor bridges between steep mountains in the rugged Shuifu county.

Head drive station of #5 conveyor at the SINOHYDRO Xiang Jia Ba project. This project uses 13 x CST drives and 2 x CSB braking units to deliver 3000 tons of gravel per hour on 31km of conveyors through 29km of tunnelling.

The Baldor CST™ (Controlled Start Transmission) is a patented 2-in-1 drive that combines a planetary gear reducer and a hydro-viscous clutch specifically engineered to deliver and synchronize power from multiple drives, and to control acceleration of high-inertia loads such as long-haul conveyors.

There are more than 2000 CST units in operation around the world with 1,452 of these in current operation throughout China, while a further 250 are programmed for installation in China in 2010. CSTs have a proven track record on conveyors up to 30km in length, in coal, gold, iron ore, copper and gravel mining operations, cement and power generation, as well as bulk handling port facilities.

CST™ concept illustration


DESIGN CAPABILITIES TO MEET THE CHALLENGE

The Xiang Jia Ba project planning began in 2000, and soon presented a series of unique challenges. How to deliver gravel through such rugged mountains with very few opportunities to locate head/tail drives at surface locations meant that a 5 stage conveyor network was the preferred design. SINOHYDRO began construction of infrastructure in 2005 and finished boring the nine tunnels in 2½ years. After signing the contract, Baldor set about preparing designs, including extensive static and dynamic analysis of all 5 conveyors to ensure safe operation under all foreseeable start-up, shut- down, part-load conditions and power-out situations.

During the design stage, a number of issues were detected, and Baldor convened several meetings between other OEM suppliers and SINOHYDRO to ensure that these issues were overcome. One of the issues was the downhill grade of conveyor #1. Baldor is well experienced in this area, and by integrating 2 Baldor CSB (Controlled Stop Breaking) clutch only units and 1 CST drive in the design, they were able to ensure excellent control over the downhill acceleration profile.

Also during the dynamic analysis stage, a possible issue was discovered between conveyors #2, #3 and #4. The concern was that flywheels may be required on the head drives to balance the belt drift timing. Baldor’s analysis determined that a more economical solution was to use very high inertia motor rotors on conveyors #3 and #4 to allow more drift time for these conveyor belts, otherwise they would spill excess material if the preceding belt stopped too rapidly during a power outage scenario.

The design was completed in 12 months, and during this time Baldor also provided extensive data to other OEM suppliers so that their equipment such as winches and take-ups could be manufactured and installed to the required specifications.



Xiang Jia Ba conveyor layout and control overview

OVERCOMING THE CHALLENGES OF RUGGED MOUNTAINS AND ISOLATION

Although China has an extensive and modern network of highways and toll roads, it is inevitable that to get equipment into these mountainous regions there are many small steep and winding roads to negotiate. There are also issues of isolation and language, and it is here where suppliers without suitable experience in China find the going very tough. Baldor however has developed an extensive network of regional sales and service centers, and has trained a highly capable team of Chinese born staff. This ensures that there is excellent communications with the client’sengineers and technicians, and a good knowledge of regional logistical issues.

In the case of the Xiang Jia Ba installation, most of the drives were assembled on skids and tested at Baldor’s Shanghai factory, then transported by road to the various installation locations. However, one of the most challenging installation issues occurred when dynamic analysis showed that a tripper drive should be located near midway on conveyor #3, in a totally inaccessible valley. This would provide substantial cost savings for the client by reducing costs for both the structure and belting. To overcome the lack of access to the valley, Baldor engineers decided the best solution was to split the frame into 2 pieces so that it could be delivered through the tunnel. Baldor engineers then reassembled the unit on-site.

TUNING AND COMMISSIONING

The final and most critical step in a successful installation is tuning and commissioning. This is where Baldor again out-shines all of its competitors. One of the biggest advantages of the CST technology is the inherent speed and accuracy at which the hydro-viscous clutch is able to absorb and smooth shock loads during start-up, and during continuous operation. Shock loads and surges are always present in a conveyor system and are a major cause of conveyor failure. By incorporating the hydro-viscous clutch on the output side instead of the input side of the gear reduction, the CST unit delivers superior reliability and tuning features compared to VFD and fluid- drives.

Some of the advantages with this configuration include:

Control of such a complex network of drives is also critical to the successful implementation of the design. Baldor has unparalleled experience in the deployment and integration of appropriate control strategies into a client’s network. Due to the extent of the Xiang Jia Ba project, multiple layers of control were used. As depicted in the Xiang Jia Ba overview diagram, a PLC (Programmable Logic Controller) is installed to command each cluster of CST/CSB drives. These units can be based on either AB-RSLogix, AB-Contrologix or Siemen’s platforms and can synchronize up to four drives. For this project a mixture of DH+ datahighway, ControlNet and Ethernet communications was implemented. The PLC controllers are used to provide an appropriate S-curve start-up ramp via managed hydraulic pressure to the clutch pack of each drive. Feedback information is processed continuously and programmed adjustments are made automatically on-the-run. Baldor also installed load-cell data measurement units at three locations to provide accurate belt tension information.

Baldor’s worldwide experience in installing and commissioning of conveyor systems over the past 20 years has provided a huge database of information on all scenarios. Combined with the detailed dynamic analysis for this project, it was a straight forward process to formulate an optimum starting sequence that would give good control under all load conditions, while limiting the maximum belt tension at the lowest level possible.

CST hydro-viscous clutch technology also makes it possible to:

Baldor completed the commissioning of all 5 conveyor flights over a six month period, and handed over to SINOHYDRO on the 15th of June 2007.


Baldor continues to supply SINOHYDRO with technical support, and on a recent visit to the installation, Baldor engineers met with the current project managers, Mr. Gong Zhi Guo – Vice Director, SINOHYDRO 8th Div. China Water & Electricity Eng Group, and Mr. Wan Zhong Hua – Vice Manager, who discussed current operations and were very satisfied with the reliability and operation of the CSTs and conveyor network. They explained that since production began they had achieved their targets, and at times had operated for periods of up to 18 days non-stop. The client was also appreciative of the continued support shown by Baldor, with regular visits from CST engineers. Baldor was also pleased to be able to arrange training in Shanghai for SINOHYDRO engineers so that they would be more confident in the future maintenance requirements of the drives.

Xiang Jia Ba Conveyor Configuration

Xiang Jia Ba conveyor system control centre located at the head of #5 conveyor. Computer graphic interface developed by Baldor enables operators to more easily visualize the operation they are supervising, and react more quickly to any unusual event.