Smart control rectifier transformer
Smart control rectifier transformer
Considering that the advancement of microprocessor technology and its wide application in various industries, especially control and protection, has been very impressive and significant, and also experts and specialists of cathodic protection always seek to use new methods and tools to improve protection systems. have been cathode, in this regard, it has used the ability to program and store information, as well as receive various reports from microprocessors, and while significantly increasing the accuracy of protection, increasing the life of the protected equipment, saving periodic field inspections by cathode experts, They have provided quick access to information and figures. Brena Electronic Transformer Company has completely designed and manufactured cathodic protection rectifiers with intelligent control with the knowledge and technology of the world for the first time in Iran. In this rectifier transformer, many features have been added to the cathodic protection system by using industrial microcontrollers.
The smart cathodic protection system is ideal for installation in refinery complexes, power plants, petrochemical industries, intercity pipelines, etc. In the mentioned system, the potential of different points of the system relative to the soil electrolyte is permanently transferred (by a fixed half-bridge) to the rectifier transformer, and the device puts the voltage of all points under test within the range of the cathodic protection standard by adjusting the output current. The main parts of these systems are:
Rectifier transformer with microprocessor or microcontroller control
Fixed half-cell (permanent reference electrodes)
1) Single reference control smart rectifier transformer (Constant Potential)
In single-reference smart cathodic protection systems, a permanent half-cell is used to regulate the injection current. In this way, by continuously measuring the potential of the structure under cathodic protection compared to the electrolyte in contact with the structure, the output current of the rectifier transformer is adjusted. The basis of the operation of the smart rectifier transformer control unit is the continuous control of the reference reference potential and based on that, changing the pulse width and firing angle of the thyristors, which results in a change in the output current.
2) Multi-reference intelligent rectifier transformer control
In multi-reference smart cathodic protection systems, in order to regulate the injected current, several permanent half-cells are used for potential feedback to the control unit (Figure 2-2). The microprocessor unit of this rectifier transformer consists of the following 4 parts:
1- Unit receiving input samples (potentials of permanent half batteries)
2- Input processing unit
3- Display output unit
4- analog output unit
The input unit is capable of receiving and processing samples. The processing unit first receives all the samples from the input, then increases or decreases the analog output sample according to the half-cell potentials. This function adjusts the samples in the best way.
In the case that the half-cell potential is within the protection criteria, the output remains constant. During this process, the processing unit transmits the required information to the user through the display. If the potential of the samples changes during the operation of the cathodic protection system, the processing unit immediately adapts the cathodic protection system to the new conditions of the samples by changing the output of the analog unit. One of the characteristics of the smart rectifier transformer is the possibility of serial communication based on the RS485 standard. This connection has made it possible to create a network with Bus topology. Based on this topology, all transformer rectifier devices are connected to each other through a two-wire connection and finally connected to a server device (the said server has the ability to exchange information and control with the computer).
Each of the transformers and rectifiers has its own address inside the main server. The beginning of every communication will always be from the server, so that first the server puts a signal on the bus that contains the address of the desired unit for communication. Therefore, the address has been received by all the units and the unit whose address sent from the server is equal to it is ready to receive the next information. And the next signal contains the command to receive and send information, then it provides the possibility to send other commands. With the process mentioned above, it is possible to receive various reports on the state of the cathodic protection system and the potential of the references. It is also possible to command each of the rectifier transformers and, as a result, set the potential of the references within the protection range.
It is also possible to exchange information through a landline phone (if possible) and a mobile phone SIM card. . The smart rectifier transformer has Local and Remote status, in Remote mode, the cathodic protection system is controlled by the server, and in Local mode, the required adjustment is made at the stations and by the operator.
