CISPR provides essential standards
SmartGrid EMC application
CISPR’s (International Special Committee on Radio Interference) primary role is standardization in the field of control of emissions above 9 kHz from devices and as such has published various standards that cover or can be applied to SmartGrid system emission measurements and control. To ensure protection of the radio frequency spectrum, emissions must be addressed effectively if the SmartGrid is to achieve its potential and provide benefits when deployed without interference complaints. A significant additional requirement is that SmartGrid systems must be immune to sources of interference from a wide array of wanted RF signals and RF disturbances and other events which occur at SmartGrid component installations. Controlling emissions and ensuring an adequate level of immunity must both be taken on board.
CISPR has prepared a Guide to EMC in Smart Grid which gives further insight into issues which should be taken into consideration when designing and developing equipment for connection and inter-operation with the Smart Grid.
CISPR believes that the Smart Grid must be reliable, secure and fault tolerant. If the Smart Grid were shown to be less reliable, less secure or less resistant to faults than the current power grid, it will not perform as intended. Among the issues that must be addressed is EMC which is the ability to withstand the electromagnetic (EM) environment (have sufficient immunity) without causing interference (disturbances) primarily to radio reception, but also to other digital/electronic devices. Electromagnetic disturbances of various types, from a variety of sources, have been reported and have caused performance degradation, outages, shutdowns and even large scale system failure to the power grid. EMC is thus an important factor for consideration in standards relating to the IEC SmartGrid program.
The SmartGrid needs to function properly and have full interoperability, with other electrical and electronic systems. To ensure this these systems and their components must be designed with due consideration for conducted electromagnetic emissions injected into the grid and for immunity to various electromagnetic phenomena originating from the grid. This needs to include devices that will be mounted on the outside of buildings and homes as well as in newly designed "SmartGrid enabled" appliances.
There are five broad categories of EMC events that need to be considered:
- Mutual interaction (degradation of performance) of grid-connected electric and/or electronic devices (including communication equipment) due to conducted RF disturbances in LV AC mains installations, particularly in the range 2 kHz to 150 kHz.
- RF interference from various kinds of wireless transmitters and from unintentional radiators.
- Commonly occurring EMC immunity events like electrostatic discharges, fast transients and power line disturbances.
- Coexistence of wireless transmitters so that wireless communications can be incorporated beneficially into the SmartGrid.
- High level EMC disturbances from naturally occurring events such as lightning surges and geomagnetic storms and even by intentional terrorist acts.
Items 1 to 3 above fall well within the scopes of CISPR and TC 77, respectively. Item 4 is more probably within the scope of ITU-R and item 5 is considered by TC77.
Since both the use of wireless communications and communications over power/mains lines is a key part of the SmartGrid system, the use of CISPR standards is essential to minimise the risk to both radio services and to electronic products in close proximity to SmartGrid devices. Only CISPR has this international role of standardization in the field of EMC for RF emissions.
The standards that should be referenced in all Smart Grid planning documentation for item 2 includes the following:
- CISPR 11 (Emission from industrial, scientific, and Medical devises)
- CISPR 22 (Emissions from information technology and multimedia equipment as well as receivers). This is identified in the IEC Smart Grid Standardization Roadmap.
- CISPR 16 is the also indirectly applicable. Its various parts include basic RF measurement methods and test instrumentation specifications including measurement uncertainty and is referenced in other CISPR product committee standards
- CISPR 24 for immunity of ITE in SmartGrid control and appliances/devices. This standards references much of the TC77 immunity test standards with additional information on the particular test set up and device operation
- CISPR 12/25 for vehicles provides test methods for emission measurements which is considering the impact of electrical vehicles and distributed charging stations
Here is an application of CISPR 11 that shows expected disruption of SmartGrid communications:
Power inverters and/or switched mode power supplies of user equipment are likely to cause conducted disturbances on the mains cord. These disturbances will cause performance degradation of other equipment connected to the same Smart Micro-Grid or Low Voltage a.c. mains used in a structure. SmartGrid meters that would be located at the power entrance to the structure would be controlled by SmartGrid communications and used for registration of amounts of electric energy passing through the meter. Such disturbances could affect the proper operation of the meter. There is evidence that household appliances and lighting equipment can be switched from stand-by mode to active mode of operation by these kinds of conducted disturbances when these disturbances triggered an unwanted event communicated falsely over the SmartGrid system. Action will also to have taken to supplementing existing immunity standards for such devices as well as the Smart meters themselves.
CISPR 11 contains test methods and limits which if invoked would limit this undesired response.
In summary, CISPR is engaged in the work of the SmartGrid project as it relates to those standards which it maintains