Control and Protection from the base14 December 2000
A fully integrated control and protection system has been specifically developed for the small hydro market
AFULLY integrated control and protection system can offer many benefits to the small hydro operator, according to Canada-based Powerbase Automation Systems. The company has developed a new system for those involved in hydro projects under 15MW.
The Powerbase control and protection system was developed after initial exposure to the small hydro market demonstrated that previous technology being used often came from several manufacturers, was mechanical in design, complex to set up and did not easily lend itself to either an unmanned installation or to a Scada software package. These systems were often PLC based, which by their very nature are generic in their application, combined with basic electrical protection devices with minimal capabilities to handle the intricacies of running a turbine. The main reason for this technology was cost. The station owners had very limited budgets for the purchase of such a system, therefore they were often looking for the simplest available. As such the integrated Powerbase Platform was developed to address these issues.
Powerbase is designed to be sufficiently universal for installation in most locations but also allows for mass production utilising known electronic assembly techniques. The software is simple to use, according to the company, allowing a person with minimal hydro power knowledge to programme the basic parameters, while also allowing the typical operating parameters to be pre-programmed and run in the background.
In addition to other sensors and external devices, the following modules act as the core of the system:
• Turbine control module (TCM).
• Generator protection module (GPM).
• Graphics display interface (GDI).
• Water resource transmitter (WRT).
• Scada interface module (SIM).
• System metering module (SMM).
• Hydraulic power unit (HPU).
• Expansion module (EXP).
The main benefit of the system is in its concept as a fully integrated system, referred to by the company as an application specific embedded controller system. The system is compared to a suite of software where the word processor, spreadsheet, presentation and web browser are integrated to maximise their functionality and effectiveness, while eliminating problems of compatibility.
Another feature is the pre-coded software and windows type setup software. The pre-coded software means the user does not have the time-consuming task of setting up basic operating parameters, while the setup guide allows the operator to easily navigate through screens to install specific features, change variables and optimise running parameters with the click of a mouse. As an example of the flexibility built into the system, the software contains the parameters to run both synchronous or induction generators, Francis, Kaplan, Pelton and most other turbine design configurations. It also contains the capability to adjust the turbine operating parameters with a multi-point cam table. The system will actually show a graph with reference points, where the operator can drag and drop these points to further optimise the operation of a double regulated turbine. The system has even been used to run a double wheel Francis, operating two sets of gates and based on water levels and efficiency points determining when to operate as a single wheel unit.
Other benefits of the systems include:
• Complete water level control.
• Common alarm banner covering both electrical and mechanical faults accessible through one main screen.
• The addition of the EXP means the system now adds a pseudo PLC for the larger or more complex sites.
• Telephone dial out or in with the automated telephone dialer (ATD).
• Complete Scada package allowing for remote monitoring and operating of the station.
• Integrated 'Smart' hydraulics.
• Ability to operate with third party excitation and speed governing systems.
For the small hydro market, serviceability is a major issue. When a station is not operating, the lost revenue can quickly add up. The Powerbase Platform approach allows for a module to be replaced and reprogrammed in a matter of minutes, typically by non-skilled personnel.
Other challenges have been solved with the platform says the company, including the use of the system to integrate diesel and water power generation at a coffee plantation in Panama. This installation presented some unusual challenges as the system consisted of two water turbines and two gen-sets, which were manually operated and switched off and on according to the load requirements. The Powerbase platform has allowed for the system to fully auto regulate itself, saving valuable fuel, time and money.
As with any newcomer in a well-established industry, Powerbase's biggest challenge is winning acceptance from the station owners and operators. According to the company, other developers have attempted to design such a system, only to leave after a few years. This left system owners with the problems and cost of replacing systems for which no parts were available. Powerbase Automation Systems claims it recognises the need to establish long term relationships with several partners in the industry.
The company has been working in conjunction with Natural Resources Canada (NRCan). NRCan has a long history of promoting Canadian technologies for renewable resources through a wide range of programmes, and has wide ranging experience of small hydro.
The company has also been in contact with the Hangzhou International Center and Hangzhou Regional Center for Small Hydro Power. These Chinese organisations are heavily involved in the small hydro industry and were interested in examining and integrating an unmanned system for many of their sites. As a result, Powerbase Automation Systems has delivered many systems to China.
The company also has numerous other systems installed internationally. The largest system to date is a 14MW site in western Canada. The smallest are only a few hundred kilowatts in size. This range of installations has allowed for a great deal of experiences, which have been utilised to further enhance the system. The development process now continues with development work targeted towards an integrated excitation and speed governing solution.