To ensure that interruptions in power supply are reduced to an absolute minimum, locating the fault quickly and accurately, applying selective fault isolation, and quick restoration of power are of the utmost importance. Ensuring high reliability and availability of power supply by improving SAIFI (System Average Interruption Frequency Index) and SAIDI (System Average Interruption Duration Index) values is key for utilities. It will enable them to avoid being forced to pay significant financial penalties to customers affected by power outages. More exact fault location information also translates into significantly improved safety for the utility personnel.
Driving the automation of the secondary distribution grid with advanced fault location technology
In grid automation applications, RIO600 allows current and voltage measurements from the medium voltage network utilizing ABB's accurate and lightweight sensor technology. Based on the measured values, RIO600 provides selective fault passage indication and reports it to the upper-level system for faster fault restoration.
By applying ABB’s unique, easy-to-use multifrequency admittance-based (MFA) earth-fault detection algorithm to fault passage indication, RIO600 can detect all types of earth fault with unequaled accuracy, irrespective of the type of distribution network. Applied to RIO600, fault passage indication with MFA contributes to facilitating the automation of secondary substations in the distribution network. The higher the level and degree of automation, the quicker and more accurately faults can be located to minimize interruptions in power supply.
Easy modernization of CSSs now also in rural areas with new FPI functionality
RIO600 now introduces new FPI functionality that allows selective fault passage indication based on current measurements only. This also makes ABB’s superior FPI functionality accessible to existing CSSs with only current measurement, or even without any measurement. CSSs with only current measurement capabilities are typically found in thinly populated rural areas, where adding voltage measurement, not to mention replacing the entire CSS, would be both time-consuming and expensive. Sometimes it is not even possible to add voltage measurement due to lack of space inside the CSS. Being based on current measurement only, the new FPI functionality offers a convenient and more affordable way to modernize existing CSSs when seeking to increase the degree and level of automation in the distribution network.
Fast and accurate fault location in rural areas remains as important as in urban areas. Typical faults are fallen trees on overhead lines and damage to cables caused by ground frost. Although the number of customers affected by a power outage in rural areas is not as high as in urban areas, it affects a larger geographical area. The number of substations is also smaller in rural areas and the distances between them are longer, which makes it even more important to ensure that these few substations are up to date and correspond to today’s requirements to allow optimal fault location.
Unlike fault passage indication with MFA, the new current measurement-based FPI functionality only detects earth-fault currents that pass through the measurement point and not elsewhere in the network. This makes it the perfect choice for radial networks, which are the most common type of network in rural areas, as they do not require information on the direction of the fault current. Fault passage indication with MFA, on the other hand, is also able to determine the direction of the fault as it is based on both current and voltage measurements. Therefore, it is ideal for looped networks, which are typically found in densely populated urban areas. Without knowing the direction of the fault current in a looped network, locating the fault becomes increasingly time-consuming and thereby expensive for the utilities.
As for fault passage indication with MFA, the new FPI functionality offers reliable fault passage indication also in compensated and unearthed networks – regardless of the type of earth fault and the fault resistance – where accurate and selective earth-fault detection is particularly challenging.
Remote I/O Unit RIO600 – modular, multipurpose and flexible
The modular remote I/O Unit RIO600 has been designed to expand the number of digital and analog inputs and outputs of Relion® protection and control relays and the substation management unit COM600, in both primary and secondary substations. The Modbus® TCP server connects RIO600 to various RTUs (Remote Terminal Unit), SCADA (Supervisory Control and Data Acquisition) systems and gateways in the electrical network. IEC 61850 offers seamless connectivity through fast, real-time GOOSE (Generic Object Oriented Substation Event) communication, allowing numerous signals to be transferred over Ethernet, with simplified, decreased wiring as a result. In addition, its optical interface allows long-distance communication and ensures high immunity to disturbances in the environment, such as voltage peaks that might severely damage devices in the communication network.
Combining RIO600 with the Arctic family of wireless communication products allows accessing and managing any remote asset from a central location. The centrally located M2M gateway ARM600 allows remote management of up to 1,000 RIO600 units via the Arctic communication devices, whereas the Arctic wireless controller ARC600 significantly increases the number of controllable devices, offering a cost-effective solution for utilities to manage remote assets in distribution networks.
RIO600 is as reliable and represents the same performance excellence and real-time functionality as the other Relion protection and control products. For further information, please visit the RIO600 page.