Type MWTU 11 Forward and Reverse Power Relay

Transcription

1 Type MWTU 11 Forward and Reverse Power Relay

2 Type MWTU 11 Forward and Reverse Power Relay Figure 1: MWTU 11 Features Wide power setting range Accuracy maintained at low power factors Non-volatile trip indication Measures forward and reverse power Instantaneous element Low burden Applications There are two versions of the MWTU 11 available; one for power measurement (W) and one for reactive power measurement (VAR). The MWTU 11 is suitable for the following applications: Reverse power protection of a generator against motoring The relay has sensitive settings and operates accurately for boundary conditions up to ±87.1 (0.05 power factor). The definite time characteristic ensures that maloperation does not occur due to momentary power reversals during synchronising or power swings on the system. Trip output connections should be made to the set of timedelayed output contacts. Limitation of power imported from a consumer by a utility power supply This application is an over power or forward power function in which higher settings are required. The directional discrimination is not required at such low power factors for reactive components as high as 60% of the generator rating. The operating time of the relay is not critical as fast tripping times are covered by fault detecting relays. Reverse VAR connections The single phase VAR relay may be used with a quadrature connection to measure reactive power.

3 Description The MWTU 11 is a single phase relay measuring I Cos φ, offering a wide power setting range (from 1% to 3.5% of rated power. A low quiescent current supply drain is achieved by use of a switch mode power supply. This allows the relay to work over a wide auxiliary voltage range and to be operated from either ac or dc supplies. It also gives kv isolation. A green LED indicates that a supply is present on the relay terminals. The time delay starts from either the operation or the reset of the instantaneous element, allowing the MWTU 11 to be used for either overpower or underpower applications. A non-volatile trip indication is given by a red LED and a reset push-button resets the bistable relay and trip indicator. Time (ms) 1,600 1,400 1,00 1, P s = 3.5% P s = 16% P s = 10% P s = 5% P s = 3% P s = 1% Current as multiple of P s setting Figure : Instantaneous element operating times. 1, Time (ms) P s setting (%P n ) Figure 3: Instantaneous element disengaging times. 3

4 (See note 3) Direction of power flow for instantaneous relay operation A B C P P1 S S1 (See note ) A B C A C B Phase rotation Case earth a b c IN VN Phase sensitive bridge P S V ref a f(a>b) b RL (See note 4) VAC VX L N +VE VE Case earth connection Power supply circuits Power MWTU Module terminal block viewed from rear Notes: 1. (a) CT shorting links make before (b) and (c) disconnect. (b) Short terminals break before (c). (c) Long terminal. (d) Pin terminal (PCB type).. CT connections are typical only. 3. VT connections are typical only. 4. Earthing connections (CTs) are typical only. Figure 4: Typical application diagram phase to phase reverse power connection. t RL Op RL3 Reset 1 Reset RL1 1 RL1 RL 1 RL Trip Instantaneous contacts Time-delayed contacts 4

5 Direction of power flow for instantaneous relay operation P P1 S S1 A A B (See note ) C N C B Phase rotation N A n a 7 (See note 3) IN 8 1 VN 3 Case earth (See note 4) VAC VX L +VE VE N Case earth connection Power supply circuits Module terminal block viewed from rear Notes: 1. (a) CT shorting links make before (b) and (c) disconnect. (b) Short terminals break before (c). (c) Long terminal. (d) Pin terminal (PCB type). Figure 5: Typical application phase to neutral reverse power connection. Phase sensitive bridge P S V ref a f(a>b) b RL1 Power MWTU 11. CT connections are typical only. 3. VT connections are typical only. 4. Earthing connections (CTs) are typical only. t RL Op RL3 Reset 1 Reset RL1 1 RL1 RL 1 RL Trip Instantaneous contacts Time-delayed contacts 5

6 Direction of power flow for instantaneous relay operation P P1 S S1 A B C A C B Phase rotation (See note ) C B c (See note 3) b IN VN Phase sensitive bridge P S V ref a f(a>b) b RL1 Case earth (See note 4) VAC VX L +VE VE N Case earth connection Power supply circuits Power MWTU Module terminal block viewed from rear Notes: 1. (a) CT shorting links make before (b) and (c) disconnect. (b) Short terminals break before (c). (c) Long terminal. (d) Pin terminal (PCB type).. CT connections are typical only. 3. VT connections are typical only. 4. Earthing connections (CTs) are typical only. Figure 6: Typical application diagram phase to phase reverse VAr connection. t RL Op RL3 Reset 1 Reset RL1 1 RL1 RL 1 RL Trip Instantaneous contacts Time-delayed contacts 6

7 Technical Data Ratings AC current (I n ) AC voltage (V n ) 1A or 5A Operative range 70% to 10%V n Power relay Rating Operative range (V) Phase to neutral 57.7/ / Phase to phase 100/ / VAR relay phase to phase Auxiliary voltage Nominal Operative range (V) (Vx) dc ac 4/ / / Frequency 50/60Hz Characteristics Characteristic quantity I Cos φ Relay characteristic angle 0 Burdens AC voltage burden AC current burden DC supply burden AC supply burden Less than 1VA per phase Less than 0.1VA for 1A relays and less than 0.VA for 5A rated relays at unity power factor and at rated current on any setting. Maximum burdens over full operative range. Voltage Quiescent Both output rating (W) relays (V x1 ) operated (W) 4/ / / Maximum burdens over full operative range. Voltage Quiescent Both output rating (VA) relays (V x ) operated (VA) / /

8 Setting ranges Power setting Time delay 1% to 3.5% P n in 0.5% P n steps 0.5s to 3s in 0.5s steps The time delay may be set to start from the operation or reset of the instantaneous element. Operating time characteristics Instantaneous operate time 7.4 at RCA V n I s (I 1) ms where I s = P s V n Instantaneous resetting and disengaging times at RCA Time delayed reset and disengaging times at RCA and I = multiples of I s See Figure The disengaging time at RCA, as the current is switched off, depends on the power setting P s and is shown in Figure 3. Less than 10ms from when the instantaneous output element operates or resets as applicable. Reference conditions for accuracy claims Power setting (P s ) Voltage Time delay 16% P n Ambient temperature 0 C Frequency 50Hz or 60Hz 100% V n (For relays covering more than one nominal voltage range the reference condition is the highest nominal voltage). DC auxiliary voltage Rating Reference 4s 4/54V 4V 48/15V 48V 110/50V 110V AC auxiliary voltage 4V 4V 48/69.3V 48V 100/10V 100V 8

9 Accuracy under reference conditions I Cos φ at RCA Over the operative range of P s to 0P s subject to a maximum current of I n. ±3% of the setting ±ma (for I n = 1A) or ±10mA (for I n 5A) whichever is the greater. Boundary of operation φ = ±1.5 at system angles between ±80 and ±87.1 φ = ±5 or ±5% I Cos φ (whichever is the greater) at system angles between ± 80 from RCA Note: The boundary of operation will not exceed ±90 from RCA. Instantaneous operating time ±10% or 15ms whichever is the greater, over the operative range of I s to I n where I s = P s V n and I = multiples of I s Operating time ±5% or 50ms whichever is the greater. Repeatability better than 1% Setting time better than 1% Resetting value The relay will reset when the power in the operating direction is less than 97% P s. Directional stability The relay will remain stable for 0 times I n in the restrain direction 0 times I n with V n = 0V Accuracy variation with influencing conditions Ambient temperature Operative range I Cos φ at RCA Accuracy of boundary of operation 5 C to +55 C Less than 0.05%/ C φ = ±1 at system angles between ±80 and ±87.1 φ = ±3 at system angles between ±80 from RCA Variation in operating time Less than 0.1%/ C 9

10 Frequency Operative range I Cos φ at RCA ±1% Accuracy of boundary of operation 47 5Hz or 57 6Hz φ = ±1% at system angles between ±80 and ±87.1 φ = ±3 at system angles between ±80 from RCA Variation in operating time ±1% I Cos φ at RCA ±% Contacts Instantaneous Time delayed Make and carry for 0.s Carry continuously Break Durability Loaded contact Unloaded contact 1 changeover and 1 normally open 1 changeover and 1 normally open 7500VA subject to a maxima of 30A and 300V ac or dc 5A ac or dc ac 150VA dc 50W resistive 5W L/R = 40ms subject to maxima of 5A and 300V 10,000 operations minimum 100,000 operations minimum Current transformer requirements IEC I n = 1A 5VA class 1; maximum lead resistance 1.5Ω I n = 5A 10VA class 1; maximum lead resistance 0.3Ω Voltage transformer requirements IEC VA class 1 See Figures 4, 5 and 6 for typical application diagrams 10

11 Thermal withstand Continuous withstand Current Voltage Short time withstand Current Operation indicators High voltage withstand Dielectric withstand IEC : 1997 High voltage impulse IEC : 1977 times rated value 1. times rated value For 1s 100I n with 400A maximum For 3s 57I n with 30A maximum A green LED is used to indicate volts are present on the relay and the internal dc/dc converter is operating. The operation of the time delayed element operates a red LED trip indicator. A latching relay is used to remember the state of the trip indicator, thus ensuring that the trip state is not lost if the power to the relay fails. The reset push button on the front plate resets the trip indicator. kv rms for 1 minute between all terminals and case earth. kv rms for 1 minute between all terminals of independent circuits, with terminals on each independent circuit connected together. 1kV rms for 1 minute across normally open contacts. Three positive and three negative impulses of 5kV peak, 1./50µs, 0.5J between all terminals and earth. 11

12 Electrical environment High frequency disturbance IEC : 1988 Class III Fast transient disturbance IEC : 199 Class IV IEC : 1988 Level 4 Surge immunity IEC : 1995 Level 3 DC supply interruption IEC : 1979 AC ripple on dc supply IEC : 1979 AC voltage dips IEC : 1994 AC voltage variations IEC : 1994 EMC compliance 89/336/EEC EN 5008-: 1994 EN 5008-: 1995 Product safety 73/3/EEC EN : 1993/A: 1995 EN 60950: 199/A11: kV peak between independent circuits and case. 1.0kV peak across terminals of the same circuit. 4kV,.5kHz applied directly to auxiliary supply. 4kV,.5kHz applied directly to all inputs. kv peak, 1./50µs between all groups and case earth. kv peak, 1./50µs between terminals of each group. The unit will withstand a 10ms interruption in the auxiliary supply. under normal operating conditions, without de-energising. The unit will withstand 1% ac ripple on the dc supply. The unit will withstand dips of 100%, 60% and 30% Vx each of 1.0s, 0.5s and 0ms duration. The unit will withstand voltage reductions to 40% Vx and 0% Vx with s ramp down, 1s at reduced voltage, s ramp up times. Compliance to the European Commission Directive on EMC is claimed via the Technical Construction File route. Generic Standards were used to establish conformity. Compliance with the European Commission Low Voltage Directive. Compliance is demonstrated by reference to generic safety standards. 1

13 Atmospheric environment Temperature IEC : 1988 IEC : 1990 IEC : 1974 Humidity IEC : 1969 Enclosure protection IEC 6059: 1989 Storage and transit 5 C to +70 C Operating 5 C to +55 C Cold Dry heat 56 days at 93% RH and +40 C IP50 (dust protected) Mechanical environment Vibration IEC : 1988 Response Class Seismic IEC : 1993 Severity Class 13

14 Cases Type MWTU11 relays are housed in size 4 cases, see Figure holes Ø All dimensions in mm Push button projection 10 max. 99 Panel cut-out: Flush mounting fixing details min max. 103 Reset Flush mounting. 11 Figure 7: Case outline size 4 14

15 Information required with order VAR or power relay Auxiliary voltage rating (V x ) Phase to neutral voltage rating (V n ) CT rating 15

16 ALSTOM T&D Protection & Control Ltd St Leonards Works, Stafford, ST17 4LX England Tel: 44 (0) Fax: 44 (0) Internet: ALSTOM T&D Protection & Control Ltd Our policy is one of continuous development. Accordingly the design of our products may change at any time. Whilst every effort is made to produce up to date literature, this brochure should only be regarded as a guide and is intended for information purposes only. Its contents do not constitute an offer for sale or advice on the application of any product referred to in it. ALSTOM T&D Protection & Control Ltd cannot be held responsible for any reliance on any decisions taken on its contents without specific advice. Publication R617C CPS Printed in England.