Performance Case
Instrumentation control system

Generator electrostatic capacitance leakage detection alarm project

Generator electrostatic capacitance leakage detection alarm project

Longzhong designed such a generator electrostatic capacitance leakage detection alarm project for customers, through the PLC control program to simulate the occurrence of liquid leakage and subsequent disconnection, and the PLC will automatically detect whether the generator is leaking or not. By sending the status back to the graphic control screen, the owner can understand the situation more quickly, and timely repair can reduce the chance of damage expansion.


Speaking of this case, it was Longzhong who contacted a panel industry customer located in the Science Park. Because the Science Park itself is a place with a very large amount of electricity, the owner said that sometimes there would be a power drop or a power outage. and so on. In order not to affect the production process, the factory uses diesel generators.


In the factory area, in order to avoid power outages, power cuts or other power shortages affecting the production process, in addition to installing a UPS uninterruptible power supply system, it is also a good solution to use a backup power supply. The motor is out.


When the diesel generator set has oil leakage, water leakage and air leakage, it will cause the diesel generator to increase the oil consumption, accelerate the wear of parts, and reduce the power. Since it is the power backup for the production process, in order for the generator to function, the generator must also be ready to go.
Therefore, the owner asked us Longzhong to take some protective measures for the generator, and Longzhong engineers planned to install the leakage detection on the generator, so that the personnel can find the fault at the first time and strive for timely repair time.


Regarding leakage detection, we Longzhong also made a related case before: Clean room PLC automatic leak detection.
However, this case is quite special, and in the part of detecting the leakage of liquid, "the leakage detection tape cannot be used". why? Because the principle of the liquid leakage detection belt is: the infiltrating liquid forms a conductor between the sensing poles, and the amount of water will change the impedance between them, causing the change of the current, which will trigger the internal electronic detection circuit of the water leakage controller to generate an alarm. One of the most important conditions for using the leak detection tape is that the leaked liquid must be a conductor.

Diesel generators use diesel as fuel, which will leak and leak diesel, and diesel is not inductive. In this case, it does not meet the use conditions of the leak detection belt.


In response to this case of sensing the leakage of the generator, Longzhong has made the following plans according to the needs of the owner and the assessment of the environment:
●In order to overcome the problem of environmental conditions, the electrostatic capacitance sensor is used as the sensing tool.
●With "real-time alarm" as the core requirement, the electrostatic capacitance sensor is connected to the PLC programmable controller. When liquid leakage is detected, it will send a signal back to the graphic controller and issue an alarm to notify the factory staff.

The electrostatic capacitance leakage sensor is simple to operate, and does not require daily maintenance by a dedicated person under the premise of proper use. It can not only be used to detect materials of any surface, color or property, even transparent objects. Different from the inductive sensor that can only detect metal objects, the electrostatic capacitance leakage sensor is a non-contact output method, which can increase the service life. In addition to the interference of objects around the environment, its applicable temperature range is also wider.

For more detailed introduction of electrostatic capacitance sensor, please see Longzhong Talk Gallery:Advanced Sensor Capacitance Sensing


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