A high voltage detector is a device which detects the presence of high voltage without any physical contact with the conductor.
It is used to determine whether the conductor is energized or de-energized so that it can be earthed before starting maintenance work.
Hence it gives information to the operator whether it is safe to work on the line or line needs to be earthed before starting work.
It can be used in a transmission system, distribution system, indoor substation, outdoor substation, etc.
Voltage detectors are used to check for the absence or presence of voltage on medium and high switchgear, transformers or overhead lines – electrical safety is imperative in all areas of power transmission and distribution at all voltage levels including MV, HV and EHV up to 400kV.
Voltage detectors can be used to detect live electricity anywhere, at levels between the stated voltage capabilities.
They are used to check when power is off in electric switch boxes and other wiring before beginning a project.
This device is useful during maintenance and installation.
This device is powered by batteries.
The rotary switch is present in the device.
It generally used to set the testing voltage. Suppose the line we have to test is of 11 KV then we can set the Rotary switch to 11 KV option.
This is how we can vary the voltage according to the testing purpose.
These detectors have LEDs indicators and buzzer inbuilt in the system.
When we take this device nearer to the live conductor, the buzzer starts buzzing and Red LED starts flashing.
Warning LED generally comes with a Red colour which denotes voltage is present. If the conductor is de-energized then Green LED starts flashing.
Before testing any line, please test the device is working or not. There is a test button provided in the high voltage detector to check whether all the indicators and circuitry is working properly or not.
The instruction for this generally provided by the manufacture.
When the detector is taken nearer to the conductor, the sensor present at the detector head senses the radiated electric field.
When this exceeds the threshold voltage, the buzzer starts buzzing, and the LED starts flashing.
First of all, we have to test the device using the test button on the device.
This is to check whether the device is working or not. It is working then either LED will flash or/and the buzzer will start buzzing.
Now set the rotary switch at the voltage level we have to test the line. Now connect the hot stick with the high voltage detector.
After this take the detector side towards the line and make a gap of 20-30 cm between the detector and the line.
If the line has voltage present then Red LED starts flashing and buzzer starts buzzing.
This means that it is not safe to work with the line. Firstly we have to de-energize the line and then starts working.
If the line doesn’t have voltage present then Green LED starts flashing. This means that it is safe to work with the line.
High voltage detector Applications
- It is used for finding faults in a cable.
- It is used for checking and detecting live high voltage line.
- It is used for detecting residual or induced voltages.
- It is used for checking high-frequency radiation.
- It is used in servicing neon lighting.
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