Perusahaan Listrik Negara, Indonesia: Upgrading Conventional Mechanization to an Intelligent Smart Grid
The Perusahaan Listrik Negara (PLN) is Indonesia’s state-owned electric company. It enjoys a monopoly on all electrical utilities in Indonesia. Because of aging and poorly planned infrastructure, PLNs electrical services had become unstable, and prone to brownouts. PLN decided to improve their grid automation with an upgrade that would simultaneously improve efficiency and reliability while reducing operating costs. PLN chose Moxa as one of their main partners for the upgrade. With legacy devices acquired from many different suppliers over a time period that spanned several decades, PLN faced the challenging task of integrating the new IEC 61850 hardware with a large number of proprietary protocols. To aid in the necessary conversions and to maintain communications between upstream and downstream devices, PLN used Moxa’s line of substation computers as data concentration units and front-end SCADA gateways.
• Fanless, rugged design
• Easily programmable
• High processing performance that can handle multiple, simultaneous protocol conversions that may include any of the following, and more: DNP 3.0, Modbus RTU, Modbus TCP, OPC server, all the RS serial protocols, TCP/IP, • • IEC 60870-5-101, and IEC 60870-5-104
• High performance RISC and x86 embedded computers for front-end SCADA gateways and downstream data concentration units
• Redundant power cabling
• Multiple communication interfaces: serial, Ethernet, and digital I/O
• Reliable and powerful controller for data acquisition, data computing, and graphics control
• Moxa DA-681 x86-based rackmount industrial computers for the front-end SCADA gateway
DA-681computers are used as front-end SCADA gateways at the station layer, where they collect and analyze data from the rest of the substation as well as remote field sites within their service area. After collation and analysis, the processed information is transmitted upstream for use by the next control layer.
• Moxa UC-8410 industrial RISC computers as data concentration units
UC-8410 computers are distributed throughout the service area connecting IEDs, smart meters, RTUs, protection relays, energy meters, distributed I/O, and other automation devices. These mid-level devices must utilize a variety of protocols for communication, and possess enough computing power to manage real-time protocol conversions to maintain smooth, high-bandwidth communications between the upstream and downstream segments.
Because Indonesia consists of many islands, PNL must support an enormous number of remote substations that are equipped with a huge variety of legacy devices from different suppliers. This variety of devices means that there are a lot of incompatible and proprietary protocols that must be integrated, making smooth upstream/downstream communications a time-consuming challenge.
UC-8410 computers serve in remote downstream deployments as DCUs, collecting and converting data from arrays of devices that are often running incompatible protocols. The processed data is then transmitted upstream to the station level and beyond. The UC-8410’s high processing power allows them to perform these protocol conversions in a timely fashion, and together with their versatile, abundant interfacing is one of the key reasons why these compact computers were selected to serve as DCUs. Among the protocols used are DNP 3.0, Modbus RTU, Modbus TCP, OPC server, various serial protocols, TCP/IP, IEC 60870-5-101, and IEC 60870-5-104, but this is not an exhaustive list.
Because of the distances involved, the UC-8410 DCUs use wireless networking to transmit their processed data up the control chain to the DA-681 gateways at the substation control layer.
• Fanless and cable-less computers with a solid-state hard drive and low power consumption provide a highly reliable, durable solution suitable for the extreme environmental conditions found in electrical substations
• Quick and sincere after-sale service
• Widely acknowledged expertise in substation engineering