Wireless sensor network in distribution substation (IEEE 802.15.4 / Zigbee and IEC 61850)

Wireless communication in IEC 61850

The IEC 61850 standard requires that communication between the devices must be wired via fiber optic or cable. This is so for they are mature technologies that ensure compliance with the requirements of the standard.

However, great strides have been made in new types of wireless systems in the non-industrial arena, in particular, data over cellular phone systems and the IEEE 802 series. Personal and commercial wireless data communications systems are becoming widespread, with increasingly mature technologies and standards, as well as decreasing costs.

As such, they offer the benefits of inexpensive products, rapid development, low cost installations widespread access, and mobile communications which wired technologies and even the older wireless technologies often cannot provide.

In addition, with cyber security becoming of greater importance to the power industry, the newer wireless systems are including improved security technologies such as in the IEEE 802.11i standards.

New wireless standards are being developed in the IEEE 802.11, 802.15 and 802.16 series which could become very useful in certain electrical substations applications

Currently there are five different types of wireless technologies considered more mature and capable of meeting the requirements of the standard.

These technologies are:

1. WiFi – IEEE 802.15.1
2. Bluetooh – IEEE 802.15.7
3. ZigBee – IEEE 802.15.4
4. Wimax – IEEE 802.16 and
5. Cellphone – Group Speciale Mobile (GSM)

As illustrated on Figure 1, these technologies are the most common for wireless communication, which are compared in terms of cost/complexity, power consumption and data rates.

The sizes of data packets to be transmitted between devices on the electrical substation are low size, from 80 bytes to 1000 bytes depending on the number of devices to control and monitor. Therefore, is not necessary to have a technology that has a high data rate but one that can guarantee that the requirements for communications between devices are met as well as low cost.

Verifying the Figure 1, the technology that possesses all these characteristics (low cost, low complexity and enough data rate) is the IEEE 802.15.4 with ZigBee.

However, before implementing the IEC 61850 on this technology, it shall be necessary to analyze the ability of this technology to meet the requirements of IEC 61850 standard.

The following subsections in this thesis will describe the IEEE 802.15.4/Zigbee and offer an analysis of this technology when applied with the IEC 61850 standard.