Page 1 Description and Explanatory Notes t equipment QT2d is designed for testing the tripping devices of the type QR3S .... for t-circuit current limiters. In conjunction with the test insert QE2a, the test equipment enables the tripping equipment including the connected tripping circuits to be subjected to 2 comprehensive test. It should be emphasized that the setting of the resistances incorporated in the metering circuits as well as the threshold values of the actual metering elements will be examined. {rip circuit of the Is-limiter consists basically of a group of measuring elements which can be compared with the protective relays generally included in protection circuits, and the eneray storage elements for igniting the charges In the Is-limiter insert. Although all possible Precautions are taken in the layout of the circult, in the choice of components and in the ‘mechanical and electrical design, it is, nevertheless, recommended, for safety reasons, to follow the practice adopted for all protective relays and prove the correct functioning of the tripping device by testing at regular intervals, The design of thi ipment ‘The dimensions of the test equipment are 400 x 215 x 320 mm (Width x Height x Depth); It can be supplied in two versions: for connecting to a single-phase A.C. supply of 200 V to 250 V, 50/60 Hz and for 100 to 130 V, 50/60 Hz. The connection to the tripping unit is effected by a multi-core cable, one’s end will joined to the test equipment while the other end terminates in a multipoint plug which is plugged into the test-socket strip of the respective tripping unit to be tested, Remark: Based on a modification of the tripping unit, done In October 2003, the marking of the test-socket strip of the tripping unit [b1] and of the test equipment [b7) can differ. Table A shows the correlation of the test socket marking between the test equipment QT2d and~ the respective tripping unit. [festeauioment [or [4 [2 [3 | n[a [ela [s pe] [eeong unt Tou.[ a [a nfz[afselss| - | Peripping unit 6 | 07 | tne Sos via a I [os [is [ee [7 [oe | In order to enable carrying-out of the tests described below, the test equipment contains a test pulse emitter, a component tester, a metering voltage source, a current source with an ammeter and a voltmeter. For a further description, see section 1,5, peiee-erwvetiscin ‘VBA730000P0102_BA C24 eng 2011-08.doe 02052011 ———Page 2 esign and method of operation of the tripping device OR3S tbe useful bo proses Webated daseroton Of ast of fhe teping Unie TY OSE of the Mee ees coutine of the basi features of the tripping device eee to the extent t equipment by an outing of the asic Rgrprocesses, The dascrption refers ¢2 the 19 mplex (standard version) of the tripping device. re tipping deve comprises one tippog ute pr phase amare UNE COTSUPALTE Tg 3 The triping devies corres on BP a age ane an iclcaon unit to Indleats, 5? ani 5 fof three, operate sWoervise the auxiliary voltage supply. The tripping units, generally S- ve rhe "P nthe version with independerty ofeach othe, (Threeshare Pe hg. is effected only in coupling current path of the Te-imiter 19 Each tripping unit is supplied from a current transformer in the : ‘only if the following Fae ere hase, calling this current i, tripping Is to be effected ‘onditions are satisfied simultaneously a) The rate of ise Ie (= olf) ofthe cltrené fe miechave seamed exceeded 2 c="n value (tripping gradient), b) The instantaneous values ofthe current le st fll between an upper init 2nd 2 lower tim. «) The quantities named must possess the same sign Le, they must be Both Posie oF both negative at the same time, the way in which these requirements are realised wil be outind with the 2id 909° which The way in whic ate dlagram of a tipping unit of the tipping device, (YPe Q°ee (standard shows the sche connection ft should be emphasized that the numbers and, eT used in Besa rent the circuit elements do rot necessary conform fo the CoLSMeNT the Ft serend of the tripping unit. Furthermore, the method of combining ‘he circuit ora eer nterchangeable modules sometimes differs from Fig: 12) rc shown n ig, 1 the current Ie lows across the current transformer (T1] to = secnoe Carte”) fs i econdary side contains the measuring transducer 4) and) Jc1007 (2 6 aan ee ceking resistors (Rljto IRAE fe\voltegesyerising at these restore seo onal to the current le The voltage obtained atthe measuring Wanssvce’ Ot whieh Is ropetinal to the rate of rice of te current, is decoupled by a secondary winding and - after arepegation into polarities - transmitted to the resistors [RS] and [R6) ste resistors [Rt] to [R6) therefore provide voltages which are proportional to the instantancows oe curvent le oF to is rte of rise fe and, moreover, permit discrimination between the sae Er ibe etc eee esas UNCON census tovon ove polaris ot tence voltage (earth) and are ulized to clear the circuit for tripping the negative care? a (Ra) ond [Ra] serve to block tripping whenever the Instantaneous value fe oats on rcssive (le>). For further clarification, Fig. 2 shows the current ie and the carting voltages against earth potential arising atthe setting resistors [Rt] to [Ré) ‘The voltages appearing at the resistors [R3] to [R6] are transmitted to the measuring aoe cr Taal by may of the two And-gates (Ui and (U2), ‘The characteristic of an And-gate cers weet of the two Input-voltages always appears on the output side, It follows that the Sutput of [U2] will equal the lower one of the voltages of [R3] *BA720000P0102 8A O72 eng 2011-06. a OTF eg czos2011the output voltage of {U2} wit equal the lower one of the voltages of Rs the fact that the outputs of the two And-gates are mutually decoupled by diode the input voltage to the measuring element 1 [U3] wil, on the other hand, always be the higher ‘one ofthe two voltages supplied By [U1] and {U2}. ne measuring element 1 (U3), a Schmitt-trigger, possesses a flip-flop characteristic and i dimensioned that It wil transmit the fring signal to the succeeding tripping pulse emitter (U5) e soon as its input voltage has been ralsed to +12 V. Due to the preceding And-gates (U3) and this can happen only if either the voltages on {R3} and (RS) of, alternatively, on (R4] and [R6) are simultaneously equal to or higher than +12 V. In this way itis ensured that, as specified above, tipping can occur only if the rate of rise and Instantaneous value of the current have attained ar exceeded a certain value (tripping ‘gradient and bottom limit) and, furthermore, f both quantities are of the same polarity. Tripping at an excessive instantaneous value of the current (le>l) 1s prevented by th onaition that the negative voltages from the resistors [Ri] and [RZ] ore transmitted to the measuring element 2 [Us]. If one of these two voltages attains the value of -12 V, ie. the operating value of the measuring element 2, the measuring element 2 will reduce the input of the measuring element 1 [U3] to zero and hold ie at this level Irrespectively of the magnitude of the voltages at the resistors [R3} to (RBI. The signals acting in the tripping direction can only actuate the measuring element 1 (U3] when |, has fallen below the instantaneous value i In the tripping condition, the thyristor in the tripping pulse emitter [US] receives the firing signal so that the tripping eapacitor [C1] discharges through the pulse transformer (73) (in the limiter insert holder) to the charge. At the same time a drop Indicator relay In the indicator panel is energized to announce the completed tripping action ("ls-limiter tripped’). he trp circuit operates with an auxiliary D.C, voltage of 150.V which Is obtained at the mains Unit by rectification of the A.C. supply. Not being stabilized, this D.C. voltage varies to the same extent as the A.C, supply voltage, Operational fluctuations of + 10 % about the mean Value of 150 V are permissible without adverse effects on the correct functioning of the tripping The voltage of all tripping capacitors {C1} is monitored by a supervisory module mounted on the mains unit, If the three voltages lie within the specified range, a further drop indicator relay (normally energized) on the indication unit will be energized. in case the capacitor voltage is too low, this relay is de-energized and the signal "Islimiter not ready” will occur. The input ‘sistance of this supervisory amplifier is indicated In Fig. 1a by the substitution resistance [Rl [Ra] causes the voltage of the capacitor {C1} fo remain always slightly below the auxiliary D.C voltage, the difference being about 12.V on the average, ‘facilitate testing, the tappings from the resistors Rt] to [R6] are connected to test sockets on the connector bi (Fig. 1a). The designation chosen for the test sockets assigns the even numbers to quantities of one polarity and the odd numbers to quantities of the opposite polarity. Furthermore, the auxiliary D.C, voltage can be measured on socket 15 and the voltage Grthe tripping eapacitor {C1} can be measured Via the protective resistance RS on socket 14 of the test socket connector bi. Wak 30000F0102_BA G72 en 2011.08 oe ‘02052011