Every distribution network operator today is aware of the tight availability requirements that societies are setting for the benefit of end customers. Since most network outages are caused by faults on the medium-voltage (MV) side, the obvious solution is MV monitoring with fault detection and the remote control of MV switching equipment. This is what the Netcon 200 was designed to provide.
Apart from enabling network operators to manoeuvre disconnectors, load switches and circuit breakers, the Netcon 200 features bidirectional MV fault detection based on four overcurrent stages and five earth fault stages per feeder. These are based on the voltage and current measurement capabilities of the Netcon 200 VCCC module. In addition to conventional overcurrent and earth fault detection, this module supports the detection of transient (intermittent) earth faults, which are a common problem with aging underground cables. All the fault stages are included in feeder-specific setting groups that can be remotely swapped when the network switching state, for example, changes.
The Netcon 200 can also offer a separately licensed, integrated feeder protection functionality for overcurrent and earth faults that trips the circuit breaker on a feeder when triggered by the relevant fault stages. It can thus replace the separate protection relays traditionally deployed at secondary substations. For example, three feeders can be protected by a single Netcon 200 device consisting of a GWDD module and a VCCC module.
Thoroughly tested, the protection includes an optional auto-reclosing functionality with three shots. This means that transient faults can often be cleared with no human intervention. But the protection can still be easily controlled, according to the circumstances, through the remotely swappable setting groups.
The real-time measurements provided by the Netcon 200 mean that the network switching state and therefore transformer loads can be better managed by the distribution management system (DMS) and/or the SCADA system. This is especially useful in exceptional situations such as during maintenance or faults. The load data and development trends also enable you to avoid over-cautious and premature renewal investments made just “to be on the safe side”.
Constant measurement of electricity quality and data available from the fault and disturbance recordings help utility companies forecast and reduce service-level disturbances in the network. Complaints from customers are reduced and customer satisfaction improves.
Effective fault detection presupposes the precise time stamping of events. The Netcon 200 can obtain time synchronisation e.g. from an NTP (Network Time Protocol) server or from the SCADA system via the communication protocol.
Through Netcontrol’s advanced sum alarm logic, the data supplied by individual alarm signals can be refined into comprehensive alarm information.
The Netcon 200 modules are compact and four modules can be combined in various ways according to the size of the secondary substation or disconnector station and the desired functionality. The configuration is through a user‑friendly web interface (WebGUI) with the help of ready-made templates.
The Netcon 200 setup always includes a GWDD module, which provides essential central processing, gateway and power supply functions for the entire Netcon 200. VCCC modules, on the other hand, are optional. Up to three can be included.
A new Netcon 200 software version and/or an expanded licence may bring about completely new applications. These include feeder protection provided that the Netcon 200 already has the required modules and sensors or that these are added.
A REST-compliant application programming interface (API) supporting multiple programming languages allows users to write their own apps for the Netcon 200. These may retrieve data from the Netcon 200, monitor changes in it, send commands to it and check logs.
In communication, the Netcon 200 supports the key protocols of today and places special emphasis on cyber security. It is linked to the SCADA network either serially or by IP connection. The IEC 60870-5-104 protocol with redundancy groups is available for IP. Connections to intelligent electronic devices (IEDs) within the substation can likewise be either serial or IP-based, the latter using the IEC 61850 protocol.
The IP communication is based on the Netcon Secure IP architecture, which enables the utility network administrator to tightly control everything that happens within the network. A built-in firewall passes only carefully selected traffic, such as remote-use and administrative connections. Control room connections are protected through encryption within OpenVPN or IPSec VPN tunnels. Users can be authenticated with RADIUS, and the unit fulfills all the modern requirements concerning Secure boot, signed patches and DDoS (distributed denial of service) attack prevention. IEC-104 links with the SCADA network can be secured in accordance with the IEC 62351 standard.
The Netcon 200 offers three user interfaces for configuration and management. The local HMI panels and the local/remote WebGUI interface provide access to a single Netcon 200 unit, including the manoeuvring of switching devices, whereas the Netcon Application Manager program, run on a web server, enables the central management of a large number of Netcon 200 (and Netcon 100) devices. Using the latter interface, you can manage the software versions and configurations, and to see the hardware setups, of Netcon 200 substations remotely. This reduces the overall cost of the system through savings in time and resources.