Surface-mounting
90 01 MON: RAM
Write or read error in the RAM area. Response: warm restart or blocking Output relay: latching
90 02 MON: Exception
Processor malfunction.
Response: warm restart or blocking Output relay: latching
90 03 MON: Parameters
Checksum error in settings area. Response: cold restart
Output relay: latching
90 08 MON: PC interface
The PC interface is defective and
blocked. Protection continues to operate. Response: PC interface blocking
Output relay: updating
90 09 MON: ILSA interface
The ILSA interface is defective and is blocked. Protection continues to operate. Response: ILSA interface blocking Output relay: updating
90 10 MON: Battery Common-RAM
The voltage of the built-in battery is too low. Replace the battery. For additional instructions see Chapter 11.
Response: none Output relay: updating
90 12 MON: Monitor sig. memory
The number of monitoring signals that can be stored has been exceeded. Response: No additional monitoring signals are stored.
Output relay: latching
90 13 MON: Signal memory
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90 16 MON: PC interface
The PC interface is defective. Response: none
Output relay: latching
90 17 MON: PC interface
Fault in the PC communications area. Response: no PC communication possible Output relay: latching
90 18 MON: PC interface
Fault in the PC communications area. Response: no PC communication possible Output relay: latching
90 21 MON: Operat. watchdog
Processor malfunction.
Response: warm restart or blocking Output relay: latching
90 25 MON: NMI
Processor malfunction.
Response: warm restart or blocking Output relay: latching
90 27 MON: Clock
Processor timer defective.
Response: warm restart or blocking Output relay: latching
90 28 MON: Cold restart
A cold restart was carried out. Response: none
Output relay: latching
90 31 MON: ILSA interface
Fault in the ILSA communication area. Response: none
Output relay: latching
90 32 MON: ILSA interface
General scan fault. Response: none Output relay: latching
90 33 MON: ILSA interface
Background general scan fault. Response: none
Output relay: latching
90 34 MON: Spontan. sig.buffer
Fault in spontaneous signal buffer area. Response: none
90 35 MON: Spontan. sig.buffer
Memory overflow. Response: none Output relay: latching
90 36 MON: ILSA/PC telegram
Telegram error (message transmission error)
Response: none Output relay: latching
90 37 MON: ILSA interface
Telegram error (message transmission error)
Response: none Output relay: latching
90 42 MON: Common-RAM
Unknown fault. Response: none Output relay: latching
90 43 MON: PC/ILSA interface
Fault in area of PC/ILSA communication. Response: none
Output relay: latching
90 70 MON: Checksum
Checksum error in the RAM area. Response: warm restart or blocking Output relay: latching
94 02 MON: Clock
Hardware clock fault.
Response: warm restart or blocking Output relay: latching
98 00 MON: Voltage meas. VLS
The voltage transformer m.c.b. on the line side has tripped.
Response: blocking of distance protection Output relay: updating
98 01 MON: Volt.meas.circuits
Negative-sequence monitoring has operated.
Response: blocking of distance protection
Output relay: updating
98 02 MON: Backup DTOC
The device has switched to backup overcurrent-time protection. Response: none
Output relay: updating
98 05 MON: Curr. meas. circuits
Negative-sequence monitoring has operated.
Response: none Output relay: updating
98 06 MON: Protect.sig.transm.
The protective signaling transmission channel is faulty.
Response: blocking of protective signaling Output relay: updating
98 07 MON: Measuring circuits
Ground starting has operated. Response: none
Output relay: updating
98 09 MON: Low voltage
A phase-to-phase voltage has fallen below the 0.4 V× nom threshold.
Response: none Output relay: updating
¨ The PD 521 signals "Block/faulty" (LED H3).
n Check to see whether a “Warning” signal is present. If so, the warning must be identified more closely, as described above.
n Check to see whether the PD 521 is deactivated (off). (This can be checked at address 03 30.)
n Check to see whether the trip command is being blocked from the local control panel (this can be checked at address 21 12).
n Check to see whether the trip command is being blocked via a binary input.
If none of the checks listed above are successful and the problem is not eliminated, send the unit to the
manufacturer along with a detailed description of the problem.
The PD 521 is a low-maintenance device. The
components used in the units are selected so that they meet exacting requirements. Recalibration is not necessary.
The PD 521 is equipped with a lithium battery for non- volatile storage of event data and for continued operation of the internal clock in the event of a failure of auxiliary voltage. Loss of capacity due to module-internal self- discharging amounts to less than 1% per year over a period of availability of 10 years. Since the terminal voltage remains virtually constant until capacity is exhausted, usefulness is maintained until a very low residual capacity is reached. Given a nominal capacity of 800 mAh and discharge currents of only a few mA during device storage and/or in the range of the self-discharge current during device operation, a correspondingly long service life results. It is therefore recommended that the lithium battery only be replaced after a period of about ten years.
The lithium battery can be replaced without soldering. Maintenance work may only be carried out by trained personnel with the auxiliary voltage turned off.
The lithium battery is located on the input-output module.
Components located behind the front panel are energized. Turn off the power supply voltage before opening the unit.
After loosening four bolts on the front side of the front panel, the local control module (front panel and processor module) can be removed once the following plugs have been removed first:
¨ The tab connector on the case
¨ The tab connector on the lower circuit board (I/O module)
¨ The ribbon cable connecting the local control module (front panel and processor module) with the I/O module ¨ The ribbon cable connecting the local control module
with the optional ILSA interface (-X7 and -X8 or -X9) Check the position of the connector. Do not allow the connecting cable to kink.
Where possible, disconnection of the ribbon cable between the processor module and the I/O module should be avoided. Should disconnection have occurred, however, then the device needs to be re-initialized by way of a cold restart.
The PD 521 is used as a safety device and must therefore be routinely checked for proper operation. It is
recommended that the first functional test be carried out after about 6 to 12 months. Additional functional tests should be carried out at intervals of about 2 to 3 years – 4 years at the maximum.
Routine Functional Testing
The PD 521 digital protection device incorporates in its system a very extensive self-monitoring function for hardware and software. The internal structure
guarantees, for example, that communication within the processor system will be checked on a continuing basis. Nonetheless, there are a number of subfunctions that cannot be checked by the self-monitoring feature without running a test from the device terminals. The respective device-specific properties and setting parameters must be observed in such cases.
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Analog Input Circuits
Within the PD 521 an analog-digital converter is used to convert analog measured variables. However, an instrument transformer, filter, analog multiplexer and 1/16 amplifier are also incorporated in each single measuring channel so that a test from the device terminals is required in order to verify proper functioning. The supply voltages are monitored continuously.
In conjunction with self-monitoring, moreover, the measuring circuit monitoring feature integrated into the protection function can in many cases exhibit a higher sensitivity and thus detect additional deviations, depending on the parameter assignment.
A static test of the analog input circuits is best carried out by operating data measurement of the primary measured operating data or by using a suitable testing device. A “small” measured value (in the current path the nominal current, for example) and a “large” measured value (in the voltage circuit the nominal voltage, for example) should be used to check the effective range of the A/D converter. In this way the total modulation range is checked, including gain change-overs. The gain change-over occurs at a modulation of 1/16 of full scale. In the distance protection function this would be at approximately 6× Inom in the current path where full modulation is 100× Inom, and in the voltage path it would be at approximately 6 V phase-to- ground voltage at the device terminals.
A check of the change-over point of gain change-over is hardly possible since the latter is determined by the hardware configuration. The only indication lies in a change in the measurement resolution. In the current path we obtain quantization levels of approximately 0 006. × Inom in the lower range and 0 1. × Inom in the upper range.
The accuracy of operating data measurement is <3%. An important factor in evaluating device performance is the long-term performance as determined from comparison with previous measurements.
This dynamic test is not absolutely necessary since it only checks the stability of a very few passive components. On the basis of reliability analysis one can expect statistically that in 10 years in 1000 devices only one component will be outside the tolerance zone.
Additional testing in the analog area, such as for the impedance or starting characteristics, is not necessary in our opinion since complete digital processing of this information is carried out on the basis of the measured analog current and voltage values. Proper operation will have been demonstrated in conjunction with the type test. The function ‘ground fault direction determination using steady-state values’ can be checked in a similar way, that is by means of operating data measurement and a test device.
Binary Inputs
The binary inputs are not checked in conjunction with self- monitoring. Therefore a test function is integrated into the device software so that the control state of the individual input can be read out at a matrix point address (54 00 and 54 03), where "0" is “low” (not triggered) and "1" is “high” (triggered). This check should be performed for each input being used, and if necessary it can be done without disconnecting the unit wiring.
Binary Outputs
There is no monitoring function for the external contact circuit. In this case triggering of the all-or-nothing relays must be initiated either by protection functions or by integrated test functions. For these testing purposes, control of the output circuits is integrated into the software by way of a special control function (address 03 43). Additionally, a test function is integrated into the unit software so that the control state of the individual output relay can be read out at a matrix point address (51 00 and up): "0" means that the output relay is inactive and "1" means that the output relay is active.
Serial Interface
The integrated self-monitoring function of the PC interface includes the communications module (UART). The entire communications system, including the interconnection and any fiber-optic module, is always completely monitored as long as a link has been created by the FPC program or the ILSA protocol.
Other Internal Functions
o Timer Stages
All timer stages in the digital protection device are derived from the precision clock pulse of the microprocessor. The oscillators have a maximum error of < ± 100 ppm. This means that a timer stage of 10 s has a maximum error of 1 ms. For this reason, it is not possible to check the accuracy of the timer stages by functional testing, since the scatter of the starting and measuring times is greater than this error. However, the processor clock frequency is checked in connection with a rough monitoring routine during startup of the protection device so that it is possible to detect complete failures. In this check during system start the clock frequency of the microprocessor module is compared with the setpoint values specified for the unit.
o Power Supply Unit
In the area of system monitoring there is a check for the presence of internal voltages. The internal operating voltages used in normal operation have approximately 50% of their maximum operational load.
The device must be stored in a dry and clean
environment. A temperature range of -25 °C to +55 °C (see Chapter 2) must be maintained. The relative humidity must not result in either condensation or ice formation.
The PD 521 is supplied with standard labeling. User- specific labeling can be written onto the reverse side of the label strips or onto blank strips available as
accessories. The label strips can be accessed from the rear of the front panel.
Turn off any auxiliary voltage before replacing the label strips. Components located behind the front panel are energized.
After four bolts on the front panel face are loosened and the tab connector (internal grounding) is detached from the rear of the front panel, it is possible to remove the local control module (front panel and processor module), which is connected to the input-output module by a plug-in ribbon cable. The label strip can be removed or inserted from the bottom of the rear of the front panel.
Before mounting the front panel, the tab connector of the grounding cable must be inserted on the rear of the front panel.
Where possible, disconnection of the ribbon cable between the processor module and the I/O module should be avoided. Should
disconnection have occurred, however, then the device needs to be re-initialized by way of a cold restart.
Labeling can be applied to the label strips by one of the following methods:
¨ Overhead projector pen, waterproof type, for example, "Stabilo" brand pen, OH Pen 196 PS.
¨ Typewriter with a pure silk fabric ribbon, for example, “Pelikan“ brand, type 58 A 371.
¨ Laser printer.
Description Order No.
Label strips
(10 sets, blank) 89512-4-0345616
Cover frame with accessories 89412-4-0338264
Battery and bracket 89512-4-0341946
PC connection cable 255 002 096 FPCC parameter assignment program 251 254 271 FPCF operating program 251 254 676
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Designs Order-No.
Distance Protection Device PD 521 89521 -0 - ¨ ¨ ¨ ¨ 0 0 ¨-302 -401 -602 -303 -402 -602 Design
Case (surface-mounting) 1
Case (flush-mounting) with cover frame 2
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Variants
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Nominal current Inom
Inom = 1A, 4-phase 1
Inom = 5A, 4-phase 2
Inom = 5A, 3-phase; Inom = 1A, 1-phase 3
Nominal frequency fnom = 50/60 Hz 2
Nominal auxiliary voltage VA,nom
VA,nom = 24 to 60 V DC / 110 to 250 V DC, 100 to 230 V AC T 3
without ILSA-communications module 0
with ILSA-communications module, to plastic fiber 1
with ILSA-communications module, to glass fiber 2
with ILSA-communications module, RS 422/485 3
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Labels & supp. documents Engl. <1> -598
Acceptance test certificate B to DIN 50049 - 3.1B <2> -599
<1> Valid for ordering prior to device production. Available as accessory (separate position) for stock items.
<2> Must be ordered prior to device production. This order extension no. will not be printed on the name label of the device or shipping box. T Settable range, delivery setting underlined.
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