Siemens SG8158-00 manual Overvoltage, Undervoltage

Protective Function Configuration

5

The range of the pickup value (2003) depends on the sec- ondary phase neutral CT rating (1 A or 5 A) and the value is in secondary amperes. The function begins timing when any individual neutral current exceeds the pickup current setting.

Note: The pickup point is 1.06 of the pickup set- ting. Refer also to paragraph on Pickup in Section 5.1.

The Time Dial (2005) used for the selected curve allows the time-to-trip of the curve to be raised or lowered The dial can be adjusted from 0.1 to 9.9 in steps of 0.1.

The Filter (2006) sets the sensing method used by the func- tion in its pickup calculations. The rms filter uses fundamen- tal current plus harmonics, while the fundamental filter ignores harmonics.

Impedance (2007) sets the angle used by this function. It determines the direction of current flow being measured and can be set from 0 to 90 degrees. The directional characteris- tic (line) in the complex impedance plane is shown in Figure 5.2. The directional characteristic is always perpen- dicular to the line impedance vector.

The sensing direction (2008) can be set to forward or reverse. The forward setting allows the directional protection element to pickup on fault current only in the direction of nor- mal power flow.

Each of the two waveform capture buffers (2010 and 2011) can be independently programmed to freeze snapshots on pickup or trip.

The Directional Neutral or Ground Time Overcurrent function is able to actuate any binary output contact on pickup, and any trip or binary output contact on trip.

The Overvoltage function can be enabled or disabled (2201).

The Curve parameter (2202) allows the selection of a definite time delay or a characteristic curve. When the definite time characteristic is selected, the time delay begins as soon as the device goes into pickup. The inverse time characteristic utilizes a moderate inverse curve using the time dial.

The Pickup Source Voltage parameter (2203) indicates the VT connection. If the VTs are connected line-to-ground, the device can pickup on line-to-line or line-to-ground voltages. If the VTs are connected line-to-line, the VTs can only pickup on line-to-line voltages. The maximum continuous voltage across a VT input is 150 VAC.

The pickup value (2204) is in secondary volts ranging from 60 to 250 V. The function begins timing when any individual phase voltage exceeds the pickup voltage setting.

The time delay (2205) represents the time between pickup and trip and can be set when definite time is selected. The delay can be adjusted from 0.1 to 60.0 seconds in steps of

0.01second. If the function remains in pickup for longer than the time delay, the function causes a trip. The delay can also be set to infinity so that the function never times out.

The Time Dial parameter (2206) is used for the characteristic curve. The dial allows the time-to-trip of the curve to be raised or lowered. It can be adjusted from 0.1 to 9.9 in steps of 0.1.

Each of the two waveform capture buffers (2210 and 2211) can be independently programmed to freeze snapshots on pickup or trip.

The function is able to actuate any binary output contact on pickup, and any trip or binary output contact on trip.

5.11 Overvoltage (59)

The Overvoltage function causes a trip if the rms value of any of the line voltages exceeds a set level. This function is only available if the voltage input option is installed.

A2200	Overvoltage (59)
Address	Parameter	Option
2201	Function	Enabled or Disabled
2202	Curve	Definite
		Inverse
		Moderately Inverse
		Very Inverse
2203	Pickup Source V	Line-to-ground
		Line-to-line
2204	Pickup	60-250 V	(0.1 V steps)
2205	Time Delay (Def.)	0.1-60 s	(0.01 s steps),
		or infinity
2205	Time Dial (Inverse)	0.1-9.9 (0.1 steps)
2210	Freeze Wfm2	on Pickup, on Trip, or None
2211	Freeze Wfm2	on Pickup, on Trip, or None

5.12 Undervoltage (27)

The Undervoltage function causes a trip if the rms value of any of the line voltages falls below a set level and can be use- ful for capturing power quality disturbances. This function is only available if the voltage input option is installed.

2300	Undervoltage 27
Address	Parameter	Option
2301	Function	Enabled or Disabled
2302	Curve	Definite
		Inverse
		Moderately Inverse
		Very Inverse
2303	Pickup Source V	Line-to-Neutral or Line-to-Line
2304	Pickup	40-230 V	(0.1 V steps)
2305	Time Delay (Def.)	0.1-60 s	(0.01 s steps),
		or infinity
2305	Time Dial (Inverse)	0.1-9.9 (0.1 steps)
2310	Freeze Wfm 2	on Pickup, on Trip, or None
2311	Freeze Wfm 2	on Pickup, on Trip, or None

26 Siemens Energy & Automation, Inc.