Softbitonline - RTCC AVR OLTC Power Transformer

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OLTC AVR RTCC Softbitonline

RTCC - AVR for OLTC of Power Transformers

GPRS enabled wireless OLTC AVR for remote monitoring & control

Onload Tap Changer (OLTC) is used with higher capacity transformers where HT side voltage variation is frequent and a nearly constant LT is required. OLTC is fitted with the transformer itself. Multiple tappings from HV windings are brought to the OLTC chamber and conacted to fixed contacts. Moving contacts rotates with the help of rotating mechanism having a spindle. This spindle can be rotated manually as well as electrically with a motor. Motor is connected in such a way that it can rotate in both the directions so as to rotate the OLTC contacts in clockwise and anticlock-wise direction. Two push buttons are fitted on the LCP (local control panel) to rotate the motor and hence the OLTC contacts in clockwise and anti-clockwise direction. This movement of contacts thus controls the output LV voltage of the transformer. So rotating of OLTC contacts with spindle or push buttons in this way is a manuall process. In case this process of rotating the OLTC contacts and hence controlling the LV side voltage is to be done automatically then a RTCC (Remote Tap Changer Controller) is installed with the transformer HT Panel. The RTCC sends signals to LCP and LCP in turn rotates the motor as per the signals received from the the RTCC.



	Microprocessor Based - Remote Tap Changer Contoller AVR (RTCC AVR)


	Dimensions: 230mm x 125mm x 100mm		Side connector blocks
	Front View		Side View

Automatic OLTC Panel consists of a LCP & a RTCC. System uses an AVR (SAG-E44) to sence the LV voltage and a comparator circuit to compare the sencing voltage with a preset value. Any difference in two sends a corresponding signal to OLTC pane to lower or raise the LV voltage of transoprmer. The OLTC control panel also has the provision to operate two or more transformers in parallel. One transformer is taken as the master and the remaining as the followers so that they follow the master's LV voltage set values.

An OLTC control panel panel is fitted with various indications to visually show the various operations being performed by the OLTC as forward and reverse movement of OLTC contacts, upper limit and lower limit indications, fault indications, interlocking indications between manual and automatic mode of the OLTC and many more.

Working of OLTC AVR Model:SAG-E44

The Automatic Voltage Regulator Relay - SAG-E44, is a totally microprocessor based relay that controls the arm movement with the help of high torque motor (OLTC and motor are not parts of the AVR supply). It also indicates the line voltage, line current, load on the transformer, apparent and reactive powers, system frequency and power factor. The AVR can be set to "Auto" or "Manual" mode. In "Auto" mode the AVR controls and maintains the transformer LV voltage as per the pre set value automatically. It sences the variations in LV voltage for a pre-set time delay and brings the voltage to normal value by changing the tap position of OLTC with the help of high torque motor. In "Manual" mode the LV voltage can be controlled through low/high push buttons which are fitted along with OLTC - LCP (Local Control Panel). Up and down movement of OLTC motor is indicated with the glow of LEDs fitted on the AVR and on the OLTC - LCP. This AVR can be used with any type of OLTC as it has to control the movement of motor which is connected with the arm that moves the contacts of the OLTC. The LCP is generally fitted near the OLTC or upon the OLTC box while the RTCC is fitted with the HT panel of the transformer.

PC/Laptop Connectivity of OLTC-AVR:
The OLTC - AVR can be connected to a desktop - PC or a laptop through RS232 communication port. The various functions of OLTC - AVR can be set from the PC/laptop and values recorded.

Overcurrent Protection of OLTC-AVR:
The OLTC - AVR is programmed to trigger an electromagnetic relay to activate an alarm in case their is a rapid voltage reduction in the system.

Parallel Mode of OLTC-AVR:
The OLTC - AVR group can operate more than one transformers in parallel mode through master-slave method.

Additional Features:

GPRS enabled for wireless data transmission:
The AVR model SAG-E44 has in-built GSM/GPRS modem for wireless operation of the OLTC AVR. The OLTC AVR can be configured, monitored & controlled from a remote central control room through SCADA software installed on your PC/Laptop. Softbitonline provides ready made SCADA software with the OLTC AVR model SAG-E44. The monitoring can also be done through a web-browser. The user has to insert a GPRS enabled SIM card from (can be purchased from a local service provider) into the SAG-E44.

Transformer Status Monitoring :
The OLTC AVR model SAG-4EE also has facility to monitor buchlotz relay status for pressure alert, gas formation alert, low oil level alert and high temperature alert through its digital contact. Apart from this model has facility to record temperature of transformer through PT100. All these parameters are sent to central control rorm through wireless system at any distance.

Transformer Energy Parameter Monitoring:
You can monitor all the energy parameters of transformer like - voltage, current, PF, Hz. KW, KWH, KVA, KVAH. This facility is available on local level on a LCD or at central control room. Automatic report/graph generation can also be done.

Please contact us with your requirement, more details and pricing on OLTC - AVR at - info@softbitonline.com

Softbit is a New Delhi, India based company. In New Delhi, Inda, the Softbitonline has its state of the art manufacturing facilities. New Delhi, India

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