The regulation system RAK205 includes the control of all the elements related to the hydraulic system for the control of speed and turbine power. It is oriented to installations where another supplier provides the control of all the auxiliary elements of the turbine (cooling, lubrication, bilge groups...) and protections of the whole assembly (temperature sensors, generation protections, Flow control, etc.).
The RAK 205 control system will control all the elements related to the water supply to the turbine installed in the plant, in the case of pelton turbines, control of regulation group, bypass, guard valve, deflectors and injectors. The aim is to provide an overall solution of the elements related to the speed-load regulation of the turbine in such a way a quick commission is done.
The RAK 205 control system will select, in case of controlling more than one regulating system and according to the established logic, the priority system to start and compensate in the opening of the following systems in order not to produce alterations in the turbine power.
The control and protection system and the RAK 205 system need to establish a relationship that as a secuence would be as follows:
| Control and protection system |
RAK 205 system |
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The external control and protection system shall include the regulation and power of all auxiliary groups except for the regulation group. It will also include the control and supply of all protection elements of both generation and turbine and interconnection.
EQUIPMENT DESCRIPTION
The regulation equipment is housed in a metal cabinet of external dimensions 1000 x 2000 x 500 made of cold-rolled steel sheet with interior and exterior protection based on RAL 7032 textured polyester-epoxy paint.
It will be accessible from the bottom and will be equipped with interior lighting, heating resistance, air inlet filter and fan with thermostat controlled filter. The cable entry is at the bottom and to facilitate the entry is provided a 80 mm high practicable socket .
Elements Arrangement at the front of the cabinet
The front of the cabinet will have the following elements:
INPUT AND OUTPUT CONNECTIONS OF THE REGULATOR MODULE:
The inputs and outputs of the system may vary depending on the type of turbine and will always adapt to the needs of the installation.
A typical configuration can be as follows:
| Digital inputs supplied by the external control system |
Digital outputs per turbine for the external control system |
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| Analog inputs supplied by the external control system |
Analog outputs for external control system |
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| External digital inputs for the RAK205 system |
External outputs of the RAK205 system |
Analog Inputs for the RAK205 System |
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DETAIL OF THE SYSTEM COMPONENTS:
Generator speed pickup without external mechanical elements
This system allows the control of the speed of the generator from the frequency of the remaining voltage of the generator. The system does not need any external mechanical or electrical equipment because it performs the measurement through the voltage reference of the generator itself. The high precision and speed of this reading allows the machine to be placed in synchronous conditions without the help of external elements.
Possibility of a redundant speed detection system by gearwheel and inductive sensors.
Control of speed with control of the regulating systems with proportional valves
The turbine speed regulating program consists of a closed loop with double feedback that drives a set of proportional valves located in the hydraulic control group.
The control systems with proportional valves make the movements of the regulating systems with an accuracy and smoothness impossible to achieve with direct valve control systems that always produce more or less abrupt variations of the generation conditions causing additionally extremely long synchronization periods.
The characteristics of the regulation are of acceleration tachometer origin with a nominal speed setpoint through a loop P I D, completely digital, feedback by the position of the regulating system and the acceleration of the machine. The acceleration control system makes it possible to perform synchronization maneuvers much faster regardless of the changes produced by the variation of net jump or any other variable involved in the regulation. The acceleration setpoint is variable as a function of the nominal speed and becomes zero when the machine is at the synchronizing speed. The control system performs automatic recalibrations of the speed control system and monitors its operation within the preset limits.
Once the generator is coupled to the grid the system calculates the position of the regulating systems depending on different variables such as: turbine type, load curve, net jump, time period, water reserve, turbine performance, Opening limiter and others.
When the desired positions of the regulating systems have been established these are brought to them through a closed loop P I D regulation loop.
The interaction of different variables such as power and level or flow rate available and the control system of the regulating devices allows, in the machines of more than one regulating system (Kaplan or Pelton) the progressive increase without sudden jumps of the power and the optimization of efficiency according to the curves of each machine. This feature is very important in specific moments in which the available flow exceeds in few points the maximum performance.
Regulation of the intake according to the operating criteria and the number of regulation systems involved.
The system can incorporate a touch screen with 2 communication ports, programmed for the modification of the working instructions, as well as to visualize and record the different parameters involved in the regulation for a better analysis.
This screen has two communication ports, one for the RAK205 and another configurable with the communication protocol for most of the companies that are currently on the market, this allows us to link setpoints or indications in digital form with the control PLC located in the destination terminal of the RAK205.
Modular and configurable control system
The regulation system RAK205 presents a totally modular configuration that allows its adaptation to the functional requirements of all type of turbines.
All of its setpoints can be adjusted from analog inputs, although the use of the operator terminal whose general characteristics are described above is more operative. If necessary, it can be programmed for access to the plant scada system to display and modify setpoints and parameters, since most mid-level or higher data acquisition programs have communication drivers for Allend Bradley PLCs .
The regulation program implemented in the CPU is a program designed specifically for hydraulic turbines by the technicians of our company and since 1993 is installed in about one hundred turbines of all types and sizes.
The system allows adjustment and modification of the regulation program and its functional logic remotely via GSM or conventional telephone line (option).
The supply of EEPROM memory modules in which the control program is installed ensures the integrity of the program in the event of a possible accident or serious damage of the system. All elements that create the controller can be replaced by trained personnel for maintenance with a minimum of indications since all the adjustments are in the program of regulation and the external cards do not have any type of programming.
EQUIPMENT DIMENSIONS:
Type of assembly dimensions:
EQUIPMENT REQUIREMENTS:
OPTIONS:
As an option to the equipment RAK205, this can be supplied with a modem, either RTC or GSM, for the adjustment of the parameters remotely, without having to move to the point in question in case there is any incidence.
A dataloguer can be adapted to the supply that allows, by means of a telecontrol program, reception of generation and level curves remotely.
The dimensions above can be modified according to the configuration of the equipment.
