1.The device overview
In the power transmission and transformation system, the transformer is the most basic and most important equipment for realizing electric energy conversion, and its safe operation plays an important role in the power system. During the operation of the transformer, the copper consumption in the windings and the iron loss in the iron core are converted into heat energy, which causes the temperature of various parts of the transformer to rise. If the heat can not be effectively and timely dissipated, the temperature of the transformer body will be too high, causing serious damage to the body and then affecting the normal operation of the transmission and distribution of the entire power grid. The service life of a transformer is mainly determined by the degree of insulation aging. The insulation aging is mainly caused by temperature changes. According to the six-degree rule of transformer insulation aging, the transformer service life is reduced by half for every 6 °C increase in temperature beyond the design temperature. It can be seen that temperature is an important indicator affecting the service life of the transformer. In 110kV, 220kV, 500kV, 1000kV oil-immersed transformers, natural oil circulation air cooling, forced oil circulation air cooling and forced oil circulating water cooling are mainly used. Most of them use natural oil circulation air cooling and forced oil. Circulating air cooling method. Transformer air-cooled intelligent control cabinet is designed for these three cooling modes. By controlling the operation of the fan and oil pump of the transformer cooling system, the effect of reducing the temperature of the transformer body can be achieved quickly and efficiently, achieving energy saving and prolonging the service life of the transformer. It is an indispensable auxiliary control system for large power transformers.

2.The use of environmental conditions
1. Installation location: outdoor, indoors
2. Ambient temperature: highest: +55°C Minimum: -40°C Maximum daily temperature difference: 25K Sunshine intensity: 0.1w/cm2
3, altitude: below 2000 meters
4, the maximum wind speed: 35m / s
5. Earthquake intensity: 8 degrees Horizontal acceleration: 0.3g Vertical acceleration: 0.15g
6, pollution level: III (2.8kv / cm)
7, ice thickness: 10mm

3.The control principle and characteristics
The device has three control modes: PLC+ electromagnetic relay type, intelligent component + soft starter type, intelligent component + inverter type.
1.PLC+ electromagnetic relay type:
Control principle: In this control mode, the main controller is mainly composed of PLC, touch screen, expansion module and peripheral relays. The main actuator consists of a contactor.
main feature:
1) Adopt dual power supply mutual investment, one master and one backup mode to ensure power supply reliability.
2) PLC control unit adopts imported brand, strong anti-interference ability and reliable operation.
3) In the case of automatic control mode failure, it can automatically switch to manual control mode and send corresponding alarm signal.
4) It can communicate with power plant DCS, unattended substation and other systems.
5) It can be controlled according to the switching amount of temperature and load, or by the analog quantity of temperature and load.
6) Large screen touch screen, friendly man-machine interface, easy to monitor and operate.
7) Install the temperature and humidity control system in the cabinet to adapt to various installation environments.
2.Intelligent component + soft starter type
Control principle: The control method is mainly composed of intelligent components and soft starters. The intelligent components are mainly composed of PLC, touch screen, transmitter, expansion module and peripheral relay. The main actuator is composed of soft starter and contactor. The intelligent component collects the operating parameters such as oil temperature and load in real time, determines the optimal control scheme of the cooling system, arranges the number of coolers reasonably, and controls the start of the cooler with a soft starter to achieve the non-impact operation of the cooling system under the small capacity working power supply. Improve the stability of the cooling system.
Main feature:
a) Adopt dual power supply mutual investment, one master and one backup mode to ensure power supply reliability.
b) Especially suitable for occasions where the power supply capacity is small and the power supply shock is required.
c) In the case of automatic control mode failure, it can automatically switch to manual control mode and send corresponding alarm signal.
d) It can communicate with power plant DCS, unattended substation and other systems.
e) It can be controlled according to the switching quantity of temperature and load, or it can be precisely controlled by the analog quantity of temperature and load.
f) Large screen touch screen, friendly man-machine interface, easy to monitor and operate.
g) The temperature and humidity control system is installed in the cabinet to adapt to various installation environments.
3.Intelligent components + inverter type
Control principle: This control method is mainly composed of intelligent components and frequency converters. The intelligent components are mainly composed of PLC, touch screen, transmitter, expansion module and peripheral relay. The main actuator is composed of inverter. The intelligent component collects the operating parameters such as oil temperature and load in real time, and determines the optimal control scheme of the cooling system accordingly, reasonably arranges the starting conditions of the cooler, the running speed, the number of operating groups, the rotation frequency, etc., to achieve energy saving, noise reduction, and improved insulation life and equipment. Life and other purposes.
main feature:
(1) Adopt dual power supply mutual investment, one master and one backup mode to ensure power supply reliability.
(2) Energy saving, environmental protection and noise reduction According to the operating parameters (oil temperature, load, winding temperature, ambient temperature, etc.), the optimal operation mode is selected to realize intelligent control, which can greatly reduce the average energy consumption and average noise index of the fan.
(3) Improve insulation life and equipment life The cooling control is optimized to achieve energy-saving and noise-reduction priority at low load, temperature-controlled cooling priority at high load, reduced oil temperature fluctuation, and efficient cooling. It can effectively improve the life of insulation materials and the operating life of fans.
(4) It can communicate with power plant DCS, unattended substation and other systems.
(5) It can be controlled according to the switching amount of temperature and load, or can be accurately controlled according to the analog quantity of temperature and load.
(6) The large-screen touch screen is adopted, and the human-machine interface is friendly, which is convenient for monitoring and operation.
(7) The temperature and humidity control system is installed in the cabinet to adapt to various installation environments.

4.The control mode
A. Manual control mode In the manual mode, all the coolers are in operation. At this time, the working state of the cooler is not affected by factors such as load current or oil temperature. B. Automatic Control Mode In the automatic mode, the control system automatically controls the operation of the cooler according to the oil temperature, load, and the like. When the running controller fails, all the cooler groups are automatically started and an alarm signal is issued.
C. Remote Control Mode In the remote control mode, the remote control room can monitor the operation of each group of coolers and can start and stop any set of coolers.

5.Technical parameters
A. Working power supply: three-phase four-wire AC dual power supply input AC380V±15%; DC input DC110V±10% or DC220V±10%;
B. Pressure resistance: ≥ AC2000V / 1min;
C. Insulation performance: ≥100MΩ;
D. Working temperature: -40 ° C ~ +55 ° C;
E. Relay output: contact capacity → AC220V/5A; isolation withstand voltage → AC2000V;
F. Communication interface: standard RS485 isolated serial port; Modbus communication protocol;
G.PLC anti-electromagnetic interference performance: in line with GB/T 14598 standard;
H. Temperature and humidity sensor: high integration; temperature measurement accuracy: ±0.3%; humidity measurement accuracy: ±2%; temperature range: -40 °C ~ +120 °C; humidity range: 0 ~ 100% RH

6.Ordering instructions
1, please specify the control cabinet control method
2, please provide transformer cooling form
3. Please provide the number and power of cooling fans.
4, the strong oil circulation type needs to provide the number of pumps and power
5, please provide relevant control contacts and terminal block diagram
6. For precise control, please provide analog of temperature and load.
7. Special working condition control can be processed according to user's special requirements.