ABB RET670 Product Manual page 20

Transformer protection RET670
Pre-configured
Product version: 1.1
evaluation of conditions from other functions
such as interlocking, synchrocheck, operator
place selection and external or internal
blockings.
Features in the apparatus control function:
• Select-Execute principle to give high
reliability
• Selection function to prevent simultaneous
operation
• Selection and supervision of operator place
• Command supervision
• Block/deblock of operation
• Block/deblock of updating of position
indications
• Substitution of position indications
• Overriding of interlocking functions
• Overriding of synchrocheck
• Operation counter
• Suppression of Mid position
Two types of command models can be used:
• Direct with normal security
• SBO (Select-Before-Operate) with enhanced
security
Normal security means that only the
command is evaluated and the resulting
position is not supervised. Enhanced security
means that the command is evaluated with an
additional supervision of the status value of
the control object. The command security
with enhanced security is always terminated
by a CommandTermination service primitive.
Control operation can be performed from the
local HMI under authority control if so defined.
Voltage control TR1ATCC, TR8ATCC,
TCMYLTC and TCLYLTC
The voltage control functions, Automatic
voltage control for tap changer, single control
(TR1ATCC,), Automatic voltage control for
tap changer, parallel control (TR8ATCC,) and
Tap changer control and supervision, 6
binary inputs (TCMYLTC,) as well as Tap
changer control and supervision, 32 binary
inputs TCLYLTC are used for control of
power transformers with a motor driven load
tap changer. The function provides automatic
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1MRK 504 091-BEN B
regulation of the voltage on the secondary
side of transformers or alternatively on a load
point further out in the network.
Control of a single transformer, as well as
control of up to eight transformers in parallel
is possible. For parallel control of power
transformers, three alternative methods are
available, the master-follower method, the
circulating current method and the reverse
reactance method. The two former methods
require exchange of information between the
parallel transformers and this is provided for
within IEC61850-8-1.
Voltage control includes many extra features
such as possibility of to avoid simultaneous
tapping of parallel transformers, hot stand by
regulation of a transformer in a group which
regulates it to a correct tap position even
though the LV CB is open, compensation for
a possible capacitor bank on the LV side bay
of a transformer, extensive tap changer
monitoring including contact wear and
hunting detection, monitoring of the power
flow in the transformer so that for example,
the voltage control can be blocked if the
power reverses etc.
Logic rotating switch for function
selection and LHMI presentation SLGGIO
The logic rotating switch for function
selection and LHMI presentation function
(SLGGIO) (or the selector switch function
block) is used to get a selector switch
functionality similar with the one provided by
a hardware selector switch. Hardware
selector switches are used extensively by
utilities, in order to have different functions
operating on pre-set values. Hardware
switches are however sources for
maintenance issues, lower system reliability
and extended purchase portfolio. The virtual
selector switches eliminate all these problems.
Selector mini switch VSGGIO
Selector mini switch (VSGGIO) function
block is a multipurpose function used in the
configuration tool in PCM600 for a variety of
applications, as a general purpose switch.
Issued: June 2010
ABB