Table. 5.4.7. - 93. Register content
Date & Time
Event
code
Fault
type
Trigger
current
Fault
current
Prefault
current
Fault
currents
Trip time
remaining
Used
SG
dd.mm.yyyy
hh:mm:ss.mss
2048-
2245
Descr.
Unbalance
Start
average
current
Trip -20ms
averages
Start -200ms
averages
I1,I2,IZ mag.
and ang.
0ms -1800s
1 – 8
5.4.8. Harmonic overcurrent Ih> (50H/51H/68H)
Harmonic overcurrent function (HOC) is used for non-directional instant- and time delayed harmonic
overcurrent detection and clearing for various applications including feeder, lter and machine
applications of utilities and industry. The number of available instances of the function depends of the
IED model. Function measures constantly selected measurement channels selected harmonic
component either on absolute value or relative to the fundamental frequency component. Blocking
signal and setting group selection controls the operating characteristics of the function during normal
operation.
Outputs of the function are Start Trip and Blocked signals. Setting parameters are static inputs for the
function which are changed only by user input in the setup phase of the function. Non directional
overcurrent function utilizes total of eight separate setting groups which can be selected from one
common source.
The function can be operating on instant or time delayed mode. If the stage is used in the instant mode
(e.g. set operating time delay is 0 s) for blocking purposes of other protection stages either Start or Trip
signal can be used. In time delayed mode the operation can be switched to de nite time or IDMT
mode. Start signal can be used for blocking other stages while in cases when the situation prolongs
can Trip signal be used for other actions as time delayed. For IDMT operation IEC and ANSI standard
time delays are supported as well as custom parameters.
The operational logic consists of input magnitude processing, input magnitude selection, saturation
check, threshold comparator, block signal check, time delay characteristics and output processing.
The basic design of the protection function is 3-pole operation.
Inputs for the function are the operating mode selections, setting parameters and measured and pre-
processed current magnitudes and binary input signals. Function outputs START, TRIP and BLOCKED
signals which can be used for direct IO controlling and also for user logic programming. The function
registers its operation into 12 last time-stamped registers and also generates general time stamped
ON/OFF events to the common event buffer from each of the three output signal. In instant operating
mode the function outputs START and TRIP events simultaneously with equivalent time stamp. Time
stamp resolution is 1ms. Function provides also cumulative counters for START, TRIP and BLOCKED
events.
In the following gure is presented the simpli ed function block diagram of the HOC function.
AQ-F255
Instruction manual
Version: 2.00
97
© Arcteq Relays Ltd