Thytronic XMR-A 4l+1A, Руководство пользователя

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FUNCTION CHARACTERISTICS
313
Magnitude matching
M(w) is a compensating factor in the current amplitude of the w side; it expresses the values that are
multiplied by the currents of the w side in order to obtain an amplitude equal to that of the currents
on one side chosen as a reference.
If inside the Set \ Base menu the
MatchType=ESTERNAL
parameter is set (external compensation
with adapter CTs), then:
M(w) = 1
However, if inside the
Set \ Base menu the
MatchType=INTERNAL
parameter is set then M(w) is
calculated by the relay as follows:
A) Calculation of the rated currents of the sides of the transformer from
S
nt
rating (in MVA) and rated
voltages V
ntH
, V
ntL
in kV programmed in the
Set \ Transformer
menu:
I
ntH
= 1000 ∙ S
nt
/ [√3 ∙ V
ntH
] rated current of side H of transformer
I
ntL
= 1000 ∙ S
nt
/ [√3 ∙ V
ntL
] rated current of side L of transformer
B) Calculation of the difference (mismatching) between the CT primary rated current and rated cur-
rent of the sides of the transformer, starting from the I
npH
, I
npL
, I
nH
, I
nL
programming parameters
inside the Set \ Base menu and from the currents calculated in the preceding paragraph:
m
H
= I
npH
/ I
ntH
mismatching coefficient on side H of transformer
m
L
= I
npL
/ I
ntL
mismatching coefficient on side L of transformer
where: I
npH
, I
npL
are the CTs rated current on sides H and L
The relay checks that the values of the mismatching coefficients are between 1.0 and 2.5, if the
condition is not met, a warning message is issued and a correction of the S
nt
, V
ntH
, V
ntL
, I
npH
, I
npL
parameters is required.
C) Choosing the transformer side
[1]
(
RefSide
) that the current amplitude compensations are taken
as a reference: the side reference chosen by the relay is the one with the lowest mismatching
coefficient. If the two sides have an equal value of the mismatching coefficient, the reference is
chosen as the side with the index H
D) If H is the reference side for current amplitude compensation, the current amplitude factors M (w)
are calculated as follows:
M
(H)
= [m
H
/ m
H]
] / [ I
nH
/ I
nH
] = 1
M
(L)
= [m
L
/ m
H]
] / [ I
nL
/ I
nH
]
If L is the reference side for current amplitude compensation, the current amplitude factors M (w)
are calculated as follows:
M
(H)
= [m
H
/ m
L]
] / [ I
nH
/ I
nL
]
M
(L)
= [m
L
/ m
L]
] / [ I
nL
/ I
nL
] = 1
Polarity matching
P (w) is the matrix of the amperometric polarity of w side. It allows us to consider each with its own
input current phase angle (coeff1 with
NORMAL
setting) or with opposite phase angle (with
coefficient -1
REVERSE
setting), allowing correction of any sw current polarity reversals due to
connection errors.
P(w) is defined as:
The coefficients of amperometric polarity (
C1-C2 POL
for p
L1(H)
,
C3-C4 POL
for p
L2(H)
,
C5-C6 POL
for p
L3(H)
,
A1-A2 POL
for p
L1(L)
,
A3-A4 POL
for p
L2(L)
,
A5-A6 POL
for p
L3(L)
) can each take the va-
lue +1 (
NORMAL
) or -1 (
REVERSE
), based on the programming of the same coefficients in the
Set \
Polarity
menu. If the amperometric polarity correspond to those of the corresponding wiring diagram
programming is +1, otherwise -1.
Phase, ciclic sequenze and zero sequenze matching
Note 1 settings of the differential protection are referred to the CT’s rated current on the side chosen by the relay as a reference for amplitude compen-
sation in (Inref).
The side chosen as a reference for amplitude compensation (RefSide) and the primary CT rated current of that side (Inref) are displayed in the
Set \ Base menu
P
(H)
= 0 p
L2(H)
0
p
L1(H)
0 0
0 0 p
L3(H)
P
(L)
= 0 p
L2(L)
0
p
L1(L)
0 0
0 0 p
L3(L)
XMR-D EQUIPMENT MANUAL
Ed. 2.9 - 02/2021