1. The Peak in Performance
Distance based line protection
.5 to 1 cycle operating times
64 samples per cycle
Series compensated line protection
The Advanced Line Protection System is an enhanced transmission line protection system which combines new techniques with established protection algorithms to give secure high speed protection. Up to now, ultra high speed protection could only be achieved using older static circuitry. The ALPS relay uses innovative methods and technology to achieve clearing times in the order of half a cycle or less for severe faults, while providing the advantages of digital technology such as oscillography, self-testing, event storage, and flexible logic and configuration checking.
The relay uses waveform sampling at 64 samples per cycle.
Models are available that will protect lines containing series capacitors, or lines adjacent to series compensated lines, using proven as well as innovative protection techniques.
While intended primarily for protecting lines where high speed clearing is critical, the relay has many features that make it attractive for any transmission line application. These include enhanced oscillography and extensive configurable logic.
Because the ALPS uses different hardware and software implementation to the DLP these relays may be used as the primary and backup protection on the same line without common failure modes.

2. Protection Features Application on any voltage line
Single and three phase tripping
Lines with series capacitor compensation
Four zones of phase and ground distance functions
Pilot ground directional overcurrent
Overcurrent backup
Selectable pilot scheme logics
Programmable logic
Programmable I/O
Out of Step Trip logic (Optional)
The ALPS relay is applicable to any transmission line. Models are available for single pole or three pole tripping and for series compensated lines.
The relay has four independent zones of distance functions for phase and ground protection. The The fourth zone can be used as the reverse blocking unit in blocking or hybrid schemes. The ground pilot scheme can be implemented with directional overcurrent functions.
Overcurrent backup, instantaneous and time overcurrent, can be used with or without directional control.
Selection can be made between among several built-in pilot schemes. The performance of these schemes has been extensively tested on the analog and digital simulators in Malvern for all kinds of internal and external faults on a wide variety of power system configurations.
Except for critical alarm outputs all inputs and outputs are configurable to user requirements. Extensive internal logic can be implemented to combine inputs with relay events to drive selected outputs. A free user-friendly windows-based graphics program (Xpression Builder) is provided to allow the user to draw the required logic and download it directly to the relay. The relay is shipped with inputs and outputs assigned to default values for those users who only require traditional capabilities.
An option for Out of Step tripping logic provides the capability of tripping for unstable system swings. The logic is similar to that in the GE OST relay.

3. Protection Algorithm Advancements
New Fourier calculation approach
Fourier built from phaselets
Fourier data purged by Fault Detector pickup
Adaptive Zone 1 reach
Reach “grows” from 33% to 100% of setting
A number of techniques are used to achieve the high speed performance in the ALPS.
Traditional Fourier techniques calculate the phasor values using samples from a half cycle or full cycle window. The ALPS relay uses a “phaselet” technique developed by GE Corporate R&D.
For Zone 1 elements, relay design must ensure that transient overreach will not cause tripping for faults beyond the end of the line. Calculation windows under one cycle can also introduce errors. In order to achieve high speed tripping without compromising security, a variable first zone reach is used in the ALPS. Initially, when only a few fault samples are available and the calculation error is high, a reduced first zone reach is used. As the number of fault samples available increases and calculation confidence builds, the first zone reach is gradually to its set value.

4. Modified Fourier Calculation
High Speed Sampling
Digital Mimic
Phaselet Calculation
Variable Window
The four major elements to the modified Fourier approach will be discussed separately.
The high speed sampling is a basic requirement to achieving speed improvement.
The digital mimic approach is a proven method of removing DC offset analogous to the transactor used in analog relays.
The phaselet calculation is a method developed by Corporate R&D and allows a faster estimate of phasors based on limited samples.
The phaselet approach allows the use of a shorter variable window which again allows a quicker decision on fault location.

5. High Speed Sampling
The ALPS samples at 64 samples a cycle but does protection calculations 16 times a cycle. 4 samples are combined to form a “Phaselet”.

6. Mimic Algorithm Time Domain: Sampled Data:
The DC transient in a sampled waveform will result in oscillations of the calculated phasor. It is desirable to remove this transient prior to calculation of the phaselets. The samples are passed through a digital mimic circuit (where the X/R ratio is set equal to that of the power system). This has the effect of eliminating the DC offset -- it is equivalent to the transactor used in the input to analog relays.

7. Phaselet Definition
Phaselets are partial sums of the products of the waveform samples and the sine/cosine coefficients.
Input signals are sampled 64 times per cycle; protection algorithms are executed 16 times per cycle.
Groups of phaselets may be scaled and added together to create a phasor.
The ALPS relay uses a “phaselet” technique developed by GE Corporate R&D. The relay samples the current and voltage waveforms at 64 times a cycle but performs the protection calculations 16 times a cycle. 4 samples are combined to calculate a “phaselet”. Phaselets are combined together to form an estimate of the phasor.

8. Phaselet Calculation
The phaselets are partial sums of the product of the waveform samples and the sine/ cosine coefficients.

9. Phasor Calculation
Phaselets are converted to phasors by the following:
Where:
Groups of phaselets may be scaled and added together to make a phasor. The technique enables the efficient calculation of phasors over windows that are not restricted to an integer multiple of a half cycle of power system frequency.
n = Phasor index (N/P) W = Window size in samples

10. Phasor Calculation
For a one cycle window, the Fourier calculation becomes:
Traditional Fourier techniques calculate the phasor values using samples from a half cycle or full cycle window. The phaselet approach allows a quick estimate of the phasors for windows less than half a cycle. When the window is equal to a full cycle the phaselet method is exactly the same as the traditional approach.

11. Variable Window
The Alps uses a variable window that expands as more fault samples are obtained.
When the Fault Detector operates, the phaselet calculation is restarted with a new expanding window.

12. Variable Window Fourier Transform
The variable window gives a quicker estimate of the phasor The fault detector is used to discard prefault samples from the calculation to improve the phasor estimation response and hence the relay speed.
For non- fault calculations, the phaselets are summed over one cycle window similar to the Discrete Fourier Transform. When the disturbance is detected the window size is reduced to one phaselet and all pre-fault samples are discarded from the calculation. As new phaselets are obtained the window is expanded and the accuracy of the phasor calculation increases. The data window expands until it reaches a full cycle and the window reverts to a one cycle window similar to conventional methods.

13. Variable Reach Zone 1
For Zone 1 elements, relay design must ensure that transient overreach will not cause tripping for faults beyond the end of the line, especially in applications with CCVT’s and high source to line impedance ratios. Calculation windows under one cycle can also introduce errors. In order to achieve high speed tripping without compromising security, a variable first zone reach is used. Initially, when only a few fault samples are available and the calculation error is high, a reduced first zone reach is used. As the number of fault samples available increases and calculation confidence builds, the first zone reach is gradually expanded to its normal value. This approach permits high speed tripping for severs close-in faults without any tendency for overreach.

14. Variable Reach Zone 1 Zone 1 reach is set to 90 % of ZL.
WINDOW SIZE % OF SET REACH
1/16 Cycle 0 (can not operate)
1/8 Cycle 33%
3/16 Cycle 65%
1/4 Cycle 75%
5/16 Cycle 83%
1/2 Cycle 90%
> 1/2 Cycle 100%
The relay initially allows quick decisions on the presence of close in severe faults by pulling back the zone 1 reach. Within a few phaselet calculations, it can be determined with confidence that the fault is within this reduced reach. As fault samples accumulate, more confidence is gained in the calculation accuracy and the first zone reach is expanded gradually to its final value.

15. MPS Test Results
This shows some model simulator testing results for the ALPS. Times shown are for SCR outputs. Relay outputs will add 4 milliseconds. Note the increase in tripping times as the fault is applied further out on the line. This is consistent with maintaining security while achieving speed and dependability requirements for severe faults.

16. Overcurrent Functions
Fault Detector
Distance function supervision
Phase & ground instantaneous units
Ground time overcurrent (TOC)
Unbalanced current alarm
Instantaneous & TOC may be directionally controlled.
Overload Alarm
The ALPS has a number of overcurrent elements which perform different functions.
The fault detector is a very sensitive detector , based on a combination of changes in sequence currents and absolute values of zero and negative sequence currents. In addition to supervising tripping it performs additional functions such as defining t =0 for most oscillography events, as trip output supervision, as input to the potential fuse failure logic, and as an input into the continuous monitor function.
Low level current detectors are used to supervise the distance units and seal in the trip bus.
The instantaneous and TOC units can be made directional or non directional. If they are directional then fuse failure will block tripping of these elements. An alternate set of non-directional overcurrent settings is available for this contingency. The TOC curve can be definite time, inverse, very inverse, extremely inverse or user defined.
The relay has unbalanced current logic that will produce an alarm signal if unbalanced currents caused by a shorted or open CT is detected.
The relay has two levels of overload alarm.

17. Voltage Functions 3 single phase undervoltage detectors
Positive sequence undervoltage detector
3 single phase over/undervoltage detectors
Potential fuse failure detection logic
Optional synch check voltage for recloser
Optional positive sequence overvoltage functions
The positive sequence voltage detector is used as input to the line pickup logic.
Over/ undervoltage with time delay is available for use in the user programmable logic.
The fuse failure logic detects loss of potential and can be used to block elements that depend on potential to prevent any misoperations due to a blown VT fuse.
An option for an extra voltage input to supervise reclosing is available.
An optional positive sequence overvoltage function is available that can calculate the compensated overvoltage at a remote location (i.e. It can calculate the Ferranti effect overvoltage at the remote terminal due to line charging current.)

18. Directional Functions
Forward and reverse negative sequence directional functions with adjustable compensation
For use in Ground Directional Over Current protection (GDOC) and to supervise instantaneous & time over current functions
The relay uses negative sequence overcurrent units to establish directionality for the overcurrent units and to supervise the tripping and blocking units if a directional ground overcurrent pilot scheme is selected.

19. Impedance Measurement
4 Zones of phase and ground mho distance functions
Zone 4 is reversible
Zones 2, 3 & 4 include independent phase and ground timers for step distance backup
Zone 1 ground may be either a mho or reactance characteristic with adaptive mho supervision
Four independent phase and ground impedance units are available. Zone 4 is reversible for use as a blocking function in a pilot scheme.
Zone 1 ground may be selected as a reactance unit with an adaptive mho supervision that gives maximum fault resistance coverage while providing security against tripping on load current.
The distance functions are variable mho units using positive sequence polarizing voltage.
Each function has a characteristic timer that can adjust the shape of the characteristic from a circle to a lens to avoid problems with the load impedance on heavily loaded lines.

20. Out-of-Step Functions
Out-of-Step Blocking
Out-of-Step Tripping
3 independent positive sequence mho distance characteristics. Option to trip entering inner characteristic, or leaving outer characteristic.
Extended oscillography data capture
The ALPS detects out of step swings that can be used to block tripping of selected distance units.
An optional out of step tripping logic is available. This logic uses three positive sequence mho characteristics to track a system swing and detect loss of synchronism. The logic distinguishes between a fault condition and a system swing and, for unstable swings, provides an output to the trip bus or to another output contact (--if it is required that a different breaker be tripped for an out of step condition.) In order to avoid large angles across the opening breaker contacts, the tripping signal can be delayed until the system swings back into phase.
If the out of step tripping option is purchased, a unique long term oscillography is captured. If out of step blocking or tripping conditions are detected, 180 cycles (60 pre event and 120 post event) of three phase voltage and current phasors, captured once per cycle are stored. This allows the user to track voltages and currents during a system swing, which typically has a period in the order of a second. Only one data file is captured and it is not written over until cleared or retrieved by the user.

21. Pilot Schemes Blocking PUTT POTT1 - Standard permissive overreaching
POTT2 - POTT with blocking functions to improve transient blocking performance
Hybrid - Includes Echo/Repeat logic and optional weak infeed tripping
Step Distance backup is included in all schemes
Programmable logic
The user can select between different pilot schemes, based on preference and application.
The POTT2 scheme is a modified POTT scheme with reverse blocking units used to provide better performance on transient current reversals due to fault clearing on parallel lines.
The Hybrid scheme is recommended where one or more terminals have weak sources that don’t provide enough current for reliable operation of the tripping units. A reverse blocking unit is applied and the absence of the blocking element pickup indicates an internal fault and a tripping signal is keyed back to the strong terminal. Weak infeed logic trips the weak terminal.
Step distance backup can be applied to supplement all schemes.
All of the above schemes have been extensively tested on the Malvern simulators. Provision for special user requirements is provided by extensive capabilities for user defined logic.

22. Other Features 4 Setting Groups Line Pickup Logic
Remote Open Detection for faster clearing of unbalanced faults
Continuous Monitor
PT Fuse Failure Detection
The ALPS has four different settings groups. The active group may be selected by a keypad command, by remote communications command, or by contact inputs.
The relay provides logic for tripping in the event of closing into a bolted fault where mho units will not operate because line side potential is not available.
The relay has a unique remote open detection which, on unbalanced faults, uses the presence of a fault followed by measurement of capacitive current on the unfaulted phases to detect that the remote terminal has cleared and then trips the local end. This speeds up tripping for faults beyond the normal zone 1 reach when there is no pilot channel.
If a protection element in the relay picks up and the fault detector does not pick up, the continuous monitor will alarm after a short period.
The logic detects blown fuses on one or more phases and can be used to alarm and/or disable protection elements that use voltage.

23. Monitoring Features Fault location calculation Event reporting
Oscillography data capture
Circuit breaker trip coil monitor
Accumulated breaker duty
Relay self test
The ALPS calculates the distance to a fault, using an algorithm that eliminates the effect of fault resistance.
A fault report is captured for each event for which oscillography is captured. Each report includes fault time, pre-fault and fault currents and voltages, fault type, distance to fault, tripping element etc. The fault information can be accessed on the Local User Interface (LUI) or using a PC.
In addition the relay stores up to 150 events such as operator action, external system events or self-test alarms.
Four output circuits are designated as trip outputs in the 3 pole relay and 6 in the single pole relay. Each of these output circuits is monitored for voltage across the open output while the breaker is closed. The output may be either a high speed contact, or an SCR.
Where the ALPS is applied on a single breaker the duty (based on I *n t where n is defined by user) and number of operations is monitored as an aid to determining maintenance requirements.
Extensive self-test on startup and background and foreground testing while running is conducted. A critical failure will cause the relay to disable protection, turn the relay status LED red, display a FAIL message, and de-energize the critical alarm relay.

24. Metering Features Local metering on LCD display
Remote metering via communications
True RMS calculation
Current: Ia, Ib, Ic, and 3I0
Voltage: Vag, Vbg, Vcg
Frequency
Three phase watts and vars
The relay has a four line liquid crystal display with adjustable contrast. Pressing the clear button causes the present values to be scrolled through, each screen of values being displayed for 4 seconds.
The present values can also be accessed by using the information key and requesting Present Values. In this mode the display values are updated by the relay every 4 seconds. The same information can be obtained remotely by communicating through one of the available ports.
The present values can be displayed as secondary or primary quantities, with the exception of the watts and vars which are always displayed in primary values.

25. RMS Metering Values
Compute RMS by taking the average of squares of each sample data
RMS values are computed 16 time per cycle based on a sliding window of one cycle
The relay calculates RMS based on 16 samples per cycle. Accuracy for currents is 1% of reading or 0.02 x In, whichever is greater; accuracy for voltage is 1% of reading, or 0.1 volt, whichever is greater.

26. Communications Features
ASCII and GE-modem protocols standard
Plug-in communications protocol converter
Front nine pin RS232 port
Rear 25 pin RS232 or 4 pin Phoenix RS485
Optional second rear 25 pin RS232/RS485
Rear ports user selectable as RS232 or RS485
All ports independently settable
The relay comes with two communication ports as standard with an option for the third. All ports are independently settable and can have different Baud rates. Each port can be configured independently for GE-modem protocol or ASCII.
Port 1 is an RS232 located on the front of the relay and is intended primarily for local PC communication. Port 2 is at the rear of the relay and can be user configured to be an RS232 or RS485 connection. Port 3 is an optional rear port, also configurable as RS232 or RS485. This port also accepts a plug in communication module. In time as different protocol conversion programs are written, this module will be be able to communicate using various communication protocols.
The flexible communications capability will allow, for example, remote communications over modem using one rear port, on-line monitoring by a station host computer or SCADA RTU using the other rear port, while allowing technician access on the front port.

27. Programmable Logic Summary
Maximum of 40 logic gates (AND, OR, NOT)
Maximum of 4 inputs per gate
Maximum of 8 programmable timers
Pickup/dropout range of 0 to 60 seconds in 1 ms steps
Maximum of 8 counters and latches
Fully assignable I/O
The ALPS Relay allows the user to configure all inputs and all outputs (except for critical alarm and power supply alarms).
The relay comes from the factory with default settings reflecting standard application. The user may use the programmable logic to redefine the inputs and what logical combinations of inputs, outputs and internally generated relay signals will operate each output contact.
A free windows based graphics program, Xpression Builder, allows the user to draw and document the required logic. The program converts the logic diagram to the required format for direct download to the relay.

28. Programmable Logic, Inputs, and Outputs
SCHEME
LOGIC
MEASURING
FUNCTIONS
PROGRAMMABLE
OUTPUTS
This is a representation of how Xpression builder is used to define how the relay will work.
Except for some critical alarm functions, none of the inputs and outputs are “hard wired” to any function. The relationships between inputs, outputs and internally generated signals is contained in a software file which is built by Xpression Builder. The ALPS is shipped with default settings. These can be modified or expanded using the program.
PROGRAMMABLE
INPUTS
PROGRAMMABLE
LOGIC

29. Expression Builder
User defines logic which program then builds into Boolean
expression for downloading to ALPS
This shows a sample logic diagram drawn with Xpression Builder. In this case one output is provided when all three breaker poles are open while another is provided, after a time delay, if only one or two poles open.

30. Recloser (Optional) Single breaker reclosing
Programmable up to 4 reclose attempts
Optional synch check/voltage supervision
An full function optional recloser can be applied and is applicable for single breaker applications. Reclosing can be initiated by an external relaying system as well as by the ALPS relay itself.
For single pole tripping models different reclosing strategies can be implemented for single pole versus three pole tripping events.
Optional synch voltage check is available with Live/ Dead Line/Bus supervision.

31. Local Interface
Multi-line 20 character LCD display for settings, fault data (faulted phases, trip type, fault location) and metering data
2 LED’s - one to indicate system status, one to indicate unacknowledged trip data
Full keypad standard
All models come with keypad and display.
The keypad has Information, Settings and Control buttons and can be used for locally viewing or changing settings, viewing present values and status and performing control functions.
A trip will result in a flashing LED as well as a flashing background on the LCD display. A trip message indicating fault time, type, tripping element and distance to the fault will be displayed.

32. Password Protection REMOTE KEYPAD VIEW SETTING SETTING NONE or CONTROL
CONTROL MASTER
MASTER
Three levels of passwords provide keypad security. No password is required to view data stored in the relay.
Four levels of security are provided for local or remote communications through a PC.
In addition hardware jumpers are provided in the relay. One jumper disables the keypad; another prevents settings changes through PC communications; the third prevents breaker operation through PC communications.

33. ASCII Command List ( 1 of 2 )
LOGIN
QUIT
PASSWORD
VALUES
READINGS
FAULT
EVENTS
OPEN
CLOSE
ENOUT
DISOUT
STATUS
SHOWSET
SET
MODEL
DATE
Each port can be configured for GEMODEM communications using ALPS-Link or for ASCII communications.
The ALPS has a built-in ASCII interface, allowing any operation, such as retrieving information, changing settings, or performing control operations that can be performed by the keypad.
Any terminal emulator such as Microsoft Windows Terminal or Procomm Plus can be used.

34. ASCII Command List ( 2 of 2 )
TIME
GROUP
TRIGGER
RELTEST
MMIPASS
UNITID
STLINID
DIGTST
REQTOC
PLAYBACK
DATARESET
OUTPUTS
INPUTS
ACCESS
END
HELP
The full list of ASCII commands is in the instruction book.

35. Oscillography Data 64 sample per cycle data including:
Currents & voltages
Contact input & output status
Internal sequence of events
Flexible triggering & event storage
2 events at 72 cycles to 16 events at 9 cycles
Optional additional memory
Files may be stored in COMTRADE format
The oscillography can be triggered by a trip, by operation of user defined elements or by external trigger.
The high sampling rate produces high resolution oscillography.
Inputs, outputs and internal relay flags can be displayed with the analog waveforms.
The standard relay can store 2 faults with 72 cycles apiece, 4 faults with 32 cycles, 8 faults with 16 cycles, or 12 faults with 10 cycles. The user can define the number of pre-fault cycles.
For events that last longer than the defined capture interval, the user can choose to split the memory available between the beginning and end of the event.
An optional expanded oscillography storage is available that will capture 7 events of 72 cycles each up to 40 events of 12 cycles each.
Oscillography can be stored in COMTRADE format, which can be displayed using the same programs supplied by Digital Fault Recorder manufacturers, or DAF format for use with GE-DATA.

36. Oscillography Data Playback
The ALPS relay has the ability to replay stored oscillography data. The data must be in the ALPS data format. The data may be fault data stored in the relay, or downloaded data stored on a PC.
The digital data is run through the ALPS protection algorithms.
Digital data in the ALPS format may be played back through the relay.
This feature could be used to determine performance of the relay with different settings. It might also be used for a quick periodic test of the relay and thus extend the period between full current and voltage injection testing.

37. Support Software ALPS-LINK: Windows based GEmodem communications
ALPS-SET: Windows based settings calculations and file creation
ALPS-TEST: Windows based test quantity calculation
Xpression Builder: Windows based programmable logic design
GE-DATA: Oscillography data analysis
The first four programs are provided free. ALPS-Link provides a user friendly communications with any port that is configured for GEmodem communications.
ALPS-SET provides the user with a program that will allow the user to create a settings file based on his application and line parameters. (Not available with the initial release.)
ALPS-TEST generates test values for the ALPS measuring units for the settings specified by the user.
Xpression Builder allows the user to easily implement the desired programmable relay logic.
GE-DATA is a separately priced option and is a powerful graphics package that allows the user to display and analyze the oscillography stored in the relay. This program is the same one used to display oscillography from other GE devices such as the DFP100, DFP200 and the DFM.

38. Upgrade Features
Flash memory allows firmware upgrades without changing relay hardware
Plug-in communications module allows for upgrade to future communications protocols
The Alps relay is designed to allow the user to take advantage of future technological improvements.
The program code resides in Flash Memory which allows the user to upgrade, when new features are available, by downloading the new software from a PC through a communication port.
Communication Protocols are continuously evolving with many different protocols in common use and others on the horizon. The use of a plug in communications module will allow the user to adopt a new protocol without otherwise modifying the relay.

39. I/O Summary Inputs: Current: Ia, Ib, Ic Voltage:
Vag, Vbg, Vcg, optional Vsynch
Digital Inputs:
8 programmable for three phase tripping
12 programmable for single phase tripping
Demodulated IRIG-B
The inputs to the relay are listed here. All contact inputs are user definable but are shipped from the factory with default values.

40. I/O Summary Outputs: 18 programmable contacts for three phase trip
24 programmable contacts for single phase trip
2 alarm contacts
(Power Supply and Critical Failure Alarms)
Analog distance to fault (SCADA)
The Power Supply and Alarm alarms are form ‘C’ contacts which operate in a fail safe mode.
The other contacts are completely user definable.
The SCADA analog output of distance to fault can be 0 to 1ma or 0 to 5V dc. The information on which phase is faulted can be assigned to selected programmable output contacts.
The trip outputs may be ordered as high speed contacts, or as SCR’s.

41. Packaging Vertical or horizontal mounting 3RU 19 inch rack mount
5.25 X vertical mount - Sized to fit the cutout of popular EM distance relays
Reversible mounting flanges
All boards may be removed from the front of the case
Each ALPS relay can be mounted horizontal or vertical by reversing the face-plate and rotating the keypad/ display.
Built in test plugs are not provided.
The front cover is attached with four thumb screws. a hole in each of the screws allows for a tamper proof installation using sealing wire.
A hole in the cover allows access to target clearing/ metering.

42. Packaging
The printed circuit boards are mounted horizontally and are connected in front via a bus card behind the front panel. The circuit boards have rear edge connectors that electrically connect with the rear terminal boards. The cards are securely held in place with guides and retaining screws. They can be removed from the front of the relay.
The magnetics module is rigidly mounted to the bottom of the case.

43. Contact Ratings Trip Alarm Channel Control Continuous Duty: 6 A
Trip Duty: 30 A for 1 second
Continuous Duty: 6 A
Pickup Time: < 4 ms
Alarm
Make & Carry: 30 A for 1 second
Pickup Time: < 8 ms
Channel Control
Power Rating: 10 W
Pickup Time: < 0.5 ms
Four of the contacts for three pole tripping models and six for single pole tripping models are trip rated (6A continuous and 30A make and carry). They have trip circuit monitoring (i.e. they monitor the voltage across the open contact or across the SCR for SCR models). The operate time is 4 milliseconds or less for contact outputs, less than 0.2 millisecond for the SCR option.
The other contacts are also rated 6A continuous and 30A make and carry but the operate time is 8 milliseconds or less.
For channel interface the standard outputs are high speed contacts, 0.5milliseconds or less. For interface with older communication sets, an optional 5V/ 20mA interface is available.

44. AC Ratings Current Inputs (Nominal 1 or 5A): Voltage Inputs:
3 X rated continuous
100 X rated for one second
50 X rated for 3 seconds
Voltage Inputs:
Nominal Voltage: (Settable)
1.2 X rated continuous
3.5 X rated for one minute, once per hour
Shown are continuous and short-time ratings.

45. DC Ratings Three models 48 VDC (38.5 - 60.0) 110/125 VDC (88 - 150)
There are three separate models based on DC supply voltage.
Jumpers are used to select an input range for the contact converters: --either 38.5 V to 300V DC or 80 V to 300 V DC. The latter might be used on 125VDC if certain inadvertent grounds could put half battery voltage on the inputs.

46. Summary of ALPS Features
High Speed Tripping for Severe Faults
Model for Series Compensated Lines
Extensive Programmable Logic and Flexible I/O
Out of Step Tripping and Extended Oscillography
Flash Memory
Full ASCII Communications
RS485 & Plug in Communication Card
Playback
Above are the main differences between the ALPS and the DLP. Except for ASCII communications, they are also the advantages over relays that have been on the market up to now.

47. ALPS Selection Guide ALPS* * * * * * * * * * * * D Distance Relay A
Revision Level 1
Single phase tripping logic 3
Three phase tripping logic
1 Ampere rated current 5
5 Ampere rated current U
For applications without Series Capacitors C
For applications with Series Capacitors
48 VDC battery voltage
110/125 VDC battery voltage 2
220/250 VDC battery voltage
SCR trip outputs & contact channel interface
Contact trip outputs & contact chan
nel interface
SCR trip outputs & 5V/20mA channel interface 4
Contact trip outputs & 5V/20mA channel interface
Front RS232 com port & 1 settable RS232/RS485 rear port (GE-Modem/ASCII)
Front RS232 com port & 2 settable RS232/RS485 rear ports (GE-Modem/ASCII) H
Horizontal mounting V
Vertical mounting S
Standard Oscillography Memory E
Extended Oscillography Memory
No Out of Step Tripping or Positive Sequence Overvoltage
With Out of Step Tripping
With Positive Sequence Overvolt
age units
With Positive Sequence Overvoltage units & Out of Step Tripping N
No recloser R
Recloser without sync-check option
Recloser with synch-check option
ALPS Selection Guide
EXAMPLE:
ALPSDA35U122VE1N = ALPS Digital Line Protection Distance Relay, Revision A, three phase tripping
relay, rated at 5 amperes, Without series capacitor protection, 110/125 VDC supply, contact tripping outputs, 2
communications ports, vertical mounting, with extended memory, without OST functions, and without recloser.