SCADA Control

=Purpose= (1)	Learning the principle and operation of Synchronous motor generator and SCADA Control system. (2)	Using PC software (which is little relative to the Programmable Logic Controller) to control the rotation speed of the generator. (3)	Able to adjust speed and frequency of the motor,and show the rotate frequency of the Synchronous motor in the scope successfully.

=Background=

The UI Department of Electrical and Computer Engineering laboratory facilities include an analog model power system (AMPS) that is capable of simulating interaction of control and protection hardware in a network with up to five lines transmission line segments. The system protection hosts a full complement of commercial protective relays and a fault generator capable of initiating common fault types with any fault impedance and any duration. Multiple generation sources can be interfaced with the system including synchronous machines, a doubly fed induction generator and power electronically coupled generation.The facility shown in Figure 1 is used for labs for several power systems courses as well as for research projects.

The model power system has controls to control a synchronous generator for manual synchronization to the Avista system through the building power supply. The manual controls include push buttons for start and start and potentiometers to control speed and terminal voltage as shown in Figure 1. The potentiometers regulator a dc control signals for the MG set. There is also a synchroscope for visual indication to determine when to manually close the circuit breaker. While the circuit breaker can be remotely controlled through a supervisory control and automation (SCADA) interface, the machine itself cannot be controlled through SCADA.

=Equipment Information and Data=

Start
Start and stop for the motor/generator set is currently controlled by two push buttons. The start pushbutton is in a normally closed position. A wire was connected to a contact on each side of the pushbutton, and these wires were then connected to a normally open relay on the back of the RTAC. On the HMI, when the Generator On button is selected, it sends a pulse to this relay which temporarily closes it. This turns on the generator.

Stop
The pushbutton that stops the generator is in a normally closed position. To turn the generator off, a mechanical relay was placed in series with the pushbutton. This relay is also normally closed to allow for the generator to run even if power to the microcontroller that is connected to the relay is lost. On the HMI, when a 1 command is sent to the microcontroller from the Generator Off button, it received by the microcontroller. The microcontroller communicates with the HMI through the RTAC using MODBUS protocol. Once, the off command is received, the microcontroller opens the relay and shuts off the generator.

Voltage/Frequency Control
Voltage and frequency adjustments are controlled by adjusting potentiometers. To add remote control, dual shafted stepper motors were used. One shaft connected to the potentiometer, and the other shaft connected to the potentiometers old knob. This allowed for both remote and manual control. The stepper motors are controlled by the microcontroller. The microcontroller receives either a voltage up, voltage down, frequency up, or frequency down value for controlling the voltage and frequency.

Breaker
Breaker 4 is the breaker being used to close the generator in with the grid. On the underside of this breaker, there are two rows of bolts for connecting wires. On the left row, the two front bolts can be used to open and close the breaker. This is done by shorting that respective bolt with any of the bolts with wires connected to them on the right-hand side. The front bolt on the left side closes the breaker, while the second one back opens it. Three wires were run from these bolts to relays on the RTAC. The open/close wires were connected to separate breakers. The third wire, the one they short too, was connected to the other side of those breakers. In the HMI, pressing the Breaker Open or Breaker Close buttons will send a pulse to that respective relay and will open or close the breaker.

=Test Bench Power up Instructions=

=Concept Selection=

Step motor
1.	Stable. Can drive a wide range of frictional and inertial loads. 2.	Needs no feedback. The motor is also the position transducer. 3.	Inexpensive relative to other motion control systems. 4.	Standardized frame size and performance. 5.	Plug and play. Easy to setup and use. 6.	Safe. If anything breaks, the motor stops. 7.	Long life. Bearings are the only wear-out mechanism. 8.	Excellent low speed torque. Can drive many loads without gearing. 9.	Excellent repeatability. Returns to the same location accurately. 10.	Overload safe. Motor cannot be damaged by mechanical overload.

Human Machine Interface(HMI)
1.	Deliver efficient HMI solutions by building effective operator interface screens through easy-to-use tools without the need for mapping data tags. 2.	Identify changing system conditions and make informed decisions based on real-time analysis without the need of any special software to view the HMI. 3.	Leverage powerful and reliable RTAC hardware with a cost-effective HMI option for local/remote monitoring, control, integrated alarms, and annunciation. 4.	Monitor your system and analyze performance anywhere, anytime with a secure, web-based, thin client user interface, which Including morphological charts, decision matrices as appropriate 5.	Access the RTAC HMI locally or remotely via a web browser interface from the web server on the RTAC unit. On demand visualization and control makes monitoring and controlling your system a more efficient task. Role-based accounts provide appropriate security access. Since it is a thin client, no installation and no upkeep for a specific application are required. 6.	The RTAC HMI offers an easy way to visualize data and create custom diagrams to monitor and control your system. The HMI provides authenticated access for multiple users from multiple locations and is viewable from a web browser. It renders natively on browsers compatible with HTML5 web standard—no plugins required.

=Installing HMI into 3530 RTAC=

=Project Schedule=

=Budget=

=MG Set Control Connections=

=Design Evaluation=

In the design validation plan, 10 requirements were listed. They also had tests listed with them. They can be seen in the table below. The requirements are on the left, and the test is on the right.

The speed of generator can be adjusted by sending a command to adjust the frequency up, or the frequency down. Per the test, the frequency dial can be seen moving. Furthermore, the measured frequency can be seen to change. Sending a command to change the voltage up, or down can also be measured by observing the changes in the voltmeter. These changes can also be seen from the measured voltages through the HMI.

The generator start button can be seen to be working by noting that the generator starts after pushing the generator on button. Similarly, the generator will turn off after pressing the generator off button.

The voltage and frequency measured through the HMI can be checked against the analog voltage and frequency meters on the analog model power system. They show similar values. Additionally, the synchroscope can be observed on the HMI to spin in a similar manner as to the manual synchroscope. Albeit, there is a small delay on the HMI based synchroscope.

Opening and closing the breaker can be verified after sending the commands from the HMI by seeing the breaker open and close. All manual controls were maintained. At this time, an autosync function does not work though.

=Future Work=

Autosync
This will require bringing in an expert with experience in either the SEL 351s or the SEL 420. If they can troubleshoot the synchronism check error and fix it, then implementing the autosync can be accomplished in less than a days worth of work. It will require doing a synchronism check, if it passes, then send command to close breaker. If it fails, then logic will adjust the voltage/frequency to within an acceptable range and rerun a synchronism check.

Remove HMI Synchroscope delay
This will also require in depth investigation, or an expert, to determine what is causing the lag on the digital synchroscope. Once the lag has been determined, then a work around can be put in place.

=Team Information=

=Additional Documentation=

Project Schedule



Meeting Minutes



Presentations



Client Interview