Our working background is operation and maintenance of EHV Transmission lines and Sub-Station.
During the operation of EHV Transmission lines, it is observed that line is tripping or auto re-close operated with out any reason in winter season i.e. ROW is cleared and insulator string is also OK.
Due to heavy fog and dusty environment this king of tripping happened. To prevent this kind of tripping we need to clean the insulator string in this environment.

But an AC EHV Transmission line length is upto 400KM i.e. more than 850 towers and in case of double circuit line total number of insulator string is about 54000. So it is very difficult to clean all insulator string in every season in charged condition.

If we identified the particular areas, where insulator string is to be cleaned then our work will be very simple. By monitoring the environment condition we can easily identified the above areas.

We can do this with the use of Pollution Sensor device. The device contained with a GR-PEACH board which is connected with a pollution sensor (SDS011 or its equivalent), Temperature & Humidity sensor, GPS Device and GSM/GPRS Modem.

The device will continuously measure the environment parameters from sensor. The environment data are stored SD Card with time stamping and also upload the data in IOT site or data analyzing center. Here GPS device is used for location & time update and GSM/GPRS Modem is used for upload the data to IOT site or data analyzing center.

We have to installed this kind of device in every one or two towers long the EHV Line. After analyzing the environment data of all device we can anticipate the area where we will do the cleaning operation of insulator string.

Bill of Material: Bill of material is used given in table below:-

Schematic circuit diagram is shown in Annx-I. GR PEACH is powered up with 5.0VDC and its injected through PIN No 05 of CN10. Output voltage 3.3VDC taken from PIN No. 02 of CN10 for other devices i.e. GPS and DHT11 (temperature & humidity sensor). GSM modem and SDS011 (PM10 and P2.5 sensor) are powered up from 5.0VDC.

/edDir/files/Annx-I_Schemetic.pdf

GPS 2509 is used for time synchronization of RTC (Real Time Clock) of GR PEACH only. Device may work from 3.3VDC to 5.0VDC. 3.3VDC is chosen for easy interfacing with GR PEACH board. Because there is no 5VDC compatible pin in GR PEACH. Rx and Tx of GPS 2509 is connected in PIN No. 09 & 10 of CN09 (serial 4) of GR PEACH respectively.

DHT11 Sensor is used for measure the environment temperature and humidity. Input voltage range of this device is also 3.3VDC to 5.5VDC. So 3.3VDC is chosen for easy interfacing. The data output pin of DHT11 is connected to PIN No. 08 of CN09 (as normal digital input pin).

SDS011 sensor is used for measure the environment pollution i.e. P10 and PM2.5. the rated inputvoltage of this device is 5.0VDC. So this device can not be connected directly with GR PEACH. Here 8 Channel 3.3V-5V 5V-3.3V IIC UART SPI TTL Level Bi-Directional Converter (BE0259) is used for converted the level of from 5.0VDC to 3.3VDC and vise-versa. Only Tx pin of SDS011 is connected to PIN No. 01 of CN14 (Serial 05) of GR PEACH via BE0259.

GSM/GPRS TTL UART Modem - SIM900 (GSM-1936) is used for uploading the processed and collected data in IOT website. Power input voltage of GSM-1936 of 4.5VDC to 12 VDC. Rxd and Txd of modem is connected to PIN No. 07 & 08 of CN14 of GR PEACH respectively. Vinf of Modem is connected to 3.3VDC to convert the interface voltage level from 5.0VDC to 3.3VDC for
interfacing with GR PEACH board.

Here, GSM modem also help to update the RTC of GR PEACH by using the local network time when GPS data is not available.

There is no dew point sensor is used to measure dew point and it may be calculated from ambient temperature and relative humidity. The formula is given below:

TD=243.04*(Ln(RH/100)+((17.625*T)/(243.04+T)))/(17.625-Ln(RH/100)-((17.625*T)/(243.04+T)))

T= ambient temperature; RH= relative humidity; TD= dew point temperature replace "T" and "TD" with your actual cell references.

In that way Ambient Temperature, Relative Humidity, Dew Point Temperature & Pollution level (PM2.5 & PM10.0) will be available with time stamping through out year in our data base. By corelating the above data base and EHV Transmission Line tripping time we can decide where string insulators to be cleaned or need replacement with polymer insulators.

At present we have no such data base. By using the above method we can improve performance of EHV TL and save out time & money.

In this project we have used https://thingspeak.com/channels/154657 for demonstration purpose. You monitoring or download the data from the above link.

Above process one of effective way to minimized the tripping as well as increase the line availability fogy & dusty winter season.

Photographs of device is given below:

Device with Enclosure Box:

Enclosure box is opened

Software:

Software is written in https://developer.mbed.org web compiler. It is very easy write in mbed
compiler. It just C compiler. The soft code is given below:

/edDir/files/source.txt