Recently, power grids evolve into smart grids with bi-directional flow of electric energy. Also renewable sources of energy are dynamically developing. In power grids, advanced IT solutions are applied what provides effective cooperation of all components of a grid in order to ensure mutual support in provided services.
The mentioned trends require to introduce crucial changes on the measurement-control level in power substations. Components of substation automation require interactions with devices (converters, protections) operating in substation bays. The application of digital communication between such devices enables easy exchange of data and information between specific elements of distributed automation in a power substation.
The SO-52-MUA controller is applied in modern, digital power substations. It is used as a specialized measurement converter of voltage and current signals from single bays of a substation. Depending on the version, the device may be installed in a bay, next to conventional current and voltage converters or may be installed in a closed room which protects against negative influence of environmental conditions. The controller cooperates with other devices of substation automation systems (SAS), using the LVDS process bus.
The SO-52-MUA controller consists of:
The device continuously measures values of voltages and currents from secondary circuits of voltage and current transducers. After processing the measurements, they are sent to receive devices using two independent communication interfaces. It enables operation in redundant structures. The interfaces apply the PRP protocol (Parallel Redundancy Protocol). It makes information transmission maximally reliable.
The SO-52-MUIO device finds its application in modern, digital power substations as a specialized unit for gathering binary signals from primary devices and required controls in power substation bays. The device provides information about current states of primary devices through the process bus. This information is required by superior substation automation system devices (SAS) to perform controls.
The controller in the basic version comprises the following modules:
Depending on the version, the device may be installed directly next to circuit breakers, disconnectors and earthing switches or in a closed room which protects against negative influence of environmental conditions.
Binary inputs, installed in the MWS-206-BH w.220 module, have hysteresis and "brushing". Hysteresis ensures stable operation of the input unit in the harsh environment of a power substation. "Brushing" is the increased value of the input current in the initial phase of controlling (ca. 50 ms). After this time, the current decreases to 1 mA. This feature increases the stability of input unit operation, without overheating input circuits. All 32 inputs in this module are galvanically separated. If it is needed, the number of inputs may be increased.
The SO-52v11-SER-PB controller performs all functions of supervision and automation in modern, digital substation bays. The controller functionally corresponds to the SO-52v11-SER controller in the range of realization of measurements, controls and signalization. It has also additional functions implemented, such as disturbance recording, fault location, power quality assessment, synchrocheck. The "PB" - version of the controller is equipped with communication interfaces used to receive measurement samples from the process bus.
The controller consists of the following modules:
The controller is not equipped with analog inputs for voltage and current measurements. Analog data is delivered using process buses. Binary data about states of substation devices is gathered also using process buses, which are also used to perform required controls.