More info
Description / Abstract:
This standard defines the interface between voltage or current
transducer systems or sensing systems with analog electronic
outputs, and suitably designed protective relays or other
substation measuring equipment. These transducer systems reproduce
the power system waveforms as scaled values.
This standard also defines requirements for optional
intermediate summing or ratio-adjusting amplifiers required to add
or subtract the outputs of more than one sensing system for
measurement by a single relay or measuring device.
Purpose
The standardized measurement signal between the transducer
system and the relay systems is characterized as an analog
electrical signal of ±11.3 V peak, at a maximum power of 3.2
mW.
A prime example of a sensing system with analog electronic
output is an optical voltage or current sensing system with an
optical-to-electronic interface. Figure 1 shows the typical
configuration of system elements for an optical current sensing
system in a high-voltage station. In this case the optical sensing
systems are located on the bus at high potential. In other cases
the sensing systems may be embedded inside power apparatus or
insulators. The optical signal is transmitted through fiber-optic
cables to the ground level before being converted to electrical
signals scaled and formatted for use by protective relays and other
intelligent electronic devices (IEDs). The optical-to-electrical
conversion module is usually located in the control house, but may
also be located near IEDs in the switchyard. This standard
specifies the electrical signals between the optical-to-electrical
conversion module and the relays or other IEDs using these
signals.
The interaction between the optical sensing system and the
conversion module is a proprietary scheme of a particular
manufacturer's sensing design, not subject to standardization. It
is the output of the conversion module, and therefore, the input of
relays and other measuring functions, that is to be standardized
here for interoperability. The marked section of Figure 1 shows the
location of the interface defined in this standard.