Closed busbarAfter years of long-term operation, the equipment of the power plant's generating units has aged, and the temperature controllers and temperature measuring elements of the power plant's temperature measuring system are frequently damaged. As a result, the temperature measurement points of various parts of the generating units cannot be monitored, increasing the workload of transportation personnel and posing a hidden danger to the safe and reliable operation of the units. It is recommended to carry out renovations as soon as possible to ensure the normal operation of the units. So, let's learn more aboutClosed busbarThe importance of the temperature measurement system!

Closed busbarPower plantofThe temperature measurement system mainly consists of thermistor temperature sensors, panel cabinets, signal cables, and the integrated control room, etc. The thermistor temperature sensors measure the temperature of various parts of the generating units through contact points, and the temperature signals are concentrated for detection on site. The temperature signals are transmitted to the control room instruments through signal lines to complete the display and monitoring of the temperature signals and participate in temperature control in real time.

Fully connected phaseClosed busbarThe ends of the container are connected by shorting plates, and a safety grounding point is set at the shorting plate connection to form a loop with the ground.。If a high induced voltage is instantaneously generated under the impact of the main transformer, the induced charges on the surface of the casing will accumulate and be immediately drawn into the ground.。Due to the large current,Closed busbara high voltage will be generated due to resistance.。This voltage may discharge to the infrared temperature measuring probe or directly installed on the casingPt100 temperature-sensing resistor, causing a soft breakdown at the weak point of the component, or introducing it into the circuit through the cable, resulting in overvoltage discharge or damage of the thermometer.

Each phase in operationClosed busbarThe alternating current produces a sinusoidally changing magnetic field in the surrounding space, and the magnetic field produces an induced potential on the aluminum closed busbar casing. Due to the three-phase full connection phase separationClosed busbarThe two ends are shorted to form a circuit, and the induced potential is generated inClosed busbarinduced current in the casing。

The induced current is basically equal to the load current of the generator, and the generated magnetic field can cancel outClosed busbarthe magnetic field generated by the alternating current. This induced current not only flows longitudinally through the entire closed busbar casing, but also flows through the infrared temperature measuring probe andPt100 temperature-sensing resistor directly installed on the casing, causing the component to generate heat.。In the fullClosed busbarbox and temperature measuring equipment, the larger the generator load current, the greater the heat generation.。InClosed busbarthe local area with high current density at the boundary between the container and the low-voltage side of the main transformer, the heat generation of this part is proportional to its resistance and the square of the current density.

Closed busbarTemperature measuring elements that are long-term exposed to such locations and environments will cause irreversible damage to electronic components, produce relatively large errors, and may cause significant damage to the equipment. Cables laid in high-voltage electrical equipment and areas with strong magnetic fields, the coexistence of electrostatic interference and electromagnetic interference are also important factors affecting temperature.。When the temperature measuring equipment is directly installed on the casing, the two ends of the metal shield are grounded, and the metal shield layer does not generate induced voltage. However, according to the Faraday's law, the interfering magnetic flux generates a grounding loop current in the shield layer, and there is a potential difference between the two grounding points, forming a large potential loop current.。

Closed busbarThe loop current cancels out the attenuation effect of the current signal, easily leading to equipment damage. In addition, the installation location of the temperature measuring equipment is close to high-current, high-voltage equipment, and the configuration of the thermometer cable also needs to pass through a complex alternating magnetic field. Due to the existence of electromagnetic interference, the thermometer that transmits the current signal is not properly grounded, which will also lead to abnormal temperature measurement and damage of the instrument.