Tv and ta disconnection of various types of protection devices

Protective device model

RCS985

TV disconnection

(1) The positive sequence voltage is less than 30V, and any phase current is 0.04In (2) The negative sequence voltage 3U2 is greater than 8V. If any of the above conditions is met, the delay 10S sends a corresponding TV disconnection alarm signal, and the abnormality disappears. After 10s delay, the signal automatically returns.

TA disconnection

The behavior of the TA disconnection alarm action of each side three-phase current loop: I2 > 0.2A + 0.25×Imax where I2: Negative sequence current, Imax: The maximum phase current satisfies the condition, and the corresponding TA abnormal alarm signal is sent after a delay of 10s. Abnormal disappearance, delay 10S automatically returns

BP2B

TV disconnection

Generator terminal voltage balance The generator end is connected to two sets of voltage transformers, and the phase-to-phase voltage and positive sequence voltage of the two sets of voltage transformers are compared to determine the TV disconnection. Action criteria:

RCS-985 generator transformer set protection device |UAB-Uab|>5V |UBC-Ubc|>5V |UCA-Uca|>5V | U1 - U1' | > 3V

Meet any of the above conditions, delay 0.2S TV disconnection alarm signal, and start TV switch

TA disconnection

The differential protection differential current alarm is only when the relevant differential protection control word is input (not related to the pressure plate input), the differential current alarm function is input, and the criterion delay 10S is reported to correspond to the differential protection differential flow alarm, and the differential protection is not blocked. The differential current disappears and the delay is 10S. To improve the sensitivity of the differential current alarm, the ratio brake differential flow alarm criterion is used: dI > di_bjzd and dI > kbj × Ires

RCS931

TV disconnection

Three-phase voltage vector sum is greater than 8 volts, protection does not start, delay 1.25 seconds to send PT disconnection abnormal signal; three-phase voltage vector and less than 8 volts, but positive sequence voltage is less than 33.3V, if bus PT is used, delay 1.25 The PT disconnection abnormal signal is sent in seconds; if the line PT is used, when any phase flow element operates or TWJ does not operate, the PT disconnection abnormal signal is sent with a delay of 1.25 seconds. The device determines whether to use the bus PT or the line PT by setting the control word. After the three-phase voltage is normal, the PT disconnection signal is reset after 10 seconds delay.

TA disconnection

The self-produced zero-sequence current is less than 0.75 times of the external zero-sequence current, or the external zero-sequence current is less than 0.75 times of the self-produced zero-sequence current, and the CT disconnection abnormal signal is delayed by 200ms; there is self-produced zero-sequence current without zero-sequence voltage And at least one phase has no flow, then the CT disconnection abnormal signal is sent after a delay of 10 seconds.

RSC925

TV disconnection

When the protection phase-to-phase current variation component and the zero-sequence current component (3I0>0.1*IN) do not operate, the following conditions are met to report the TV disconnection (or gate condition): a) Three-phase voltage vector sum greater than 12 volts, delay 1.25 The second report TV is disconnected. b) When the positive sequence voltage is less than 33V, any phase current (>0.06In) or trip position relay does not operate, and the delay is 1.25 seconds to report TV disconnection. After the three-phase voltage returns to normal, it will resume normal operation after a delay of 10 seconds.

TA disconnection

Zero-sequence long-term start alarm: When the self-produced zero-sequence current is large and 0.1IN, the 10-second delay reports the zero-sequence current long-term action alarm. When the zero-sequence current is less than 0.1IN, the delay is 10 seconds.

RCS915

TV disconnection

AC voltage disconnection alarm

1) Analog single-phase disconnection, the bus voltage 3U2 is greater than 12V, that is, when the residual voltage of the disconnected phase is <44V, the busbar is disconnected by 1.25 seconds.

2) Analog three-phase disconnection, |Ua|=|Ub|=|Uc| < 18V, and the current is greater than 0.04IN in the bus-tie TA. The bus is disconnected by 1.25 seconds.

1) Apply a three-phase balanced voltage to the voltage loop, and send a single-phase current >0.06In to any branch, and send a TA disconnection alarm signal for 5 seconds.

2) Apply a three-phase balanced voltage to the voltage loop, and enter the three-phase balanced current >IDX in any branch, and send a TA disconnection alarm signal for 5 seconds.

3) In any branch, the current is >IDXBJ, and the TA abnormal alarm signal is sent for 5 seconds.

CSC103

TV disconnection

The criterion a) is: the sum of the three-phase voltages is not zero: |UA+UB+UC|>7V (effective value) This criterion can be used to detect one-phase or two-phase disconnection.

The criterion b) is: When the PT is in the busbar, if the voltage of any phase of Ua⎥, ⎢Ub⎥ and ⎢Uc⎥ is less than 8V, it is judged as PT disconnection. When the PT is in line, when any phase current is greater than 0.04 times of rated current or the circuit breaker is in position (detecting tripping position), if any phase voltage of Ua⎥, ⎢Ub⎥ and ⎢Uc⎥ is less than 8V, it is judged as PT is broken.

TA disconnection

a) When the zero-sequence current of the device is longer than the zero-sequence starting current setting, the “CT disconnection alarm” is reported, and the zero-sequence protection is blocked;

b) Differential protection CT disconnection detection: The self-produced 3I0 value on the disconnection side is continuously greater than the zero-sequence starting current setting for 12s, while the disconnected phase current is less than 0.06In (In is the secondary side rated current); The difference current of the side is continuously greater than 0.15In for 12s and the disconnected phase current is less than 0.06In, and the "CT disconnection alarm of this side" is reported. After the contralateral CT is disconnected, the side reports “opposite CT disconnection alarm”.

CSC125A

TV disconnection

The device is provided with two criteria for detecting TV disconnection, both of which have a delay, and are only input when the line is in normal operation and the starting element is not activated. Once the starting element is activated, the TV disconnection detection is immediately stopped. Wait until the entire group is reset before recovering. Criterion a)

The sum of the three-phase voltages is not zero: |UA+UB+UC|>7V (effective value) This criterion can be used to detect one-phase or two-phase disconnection. The criterion b) is: ⎢Ua⎥, ⎢Ub⎥ and ⎢Uc⎥ are both less than 8V, and any phase current is greater than 0.04In. An additional condition is to prevent false alarms before the circuit breaker is closed when the TV is on the line side. In order to prevent the three-phase voltage loss from being alarmed when the current is too small (for example, the opposite side is not closed), the device adds a criterion that the circuit breaker is in the position (opening with the trip position) as a supplement: that the three-phase voltage is less than 8V, Even if the current is not more than 0.04 times the rated current, the circuit breaker can be alarmed if it is in the position.

TA disconnection

The zero-sequence current continuously exceeds 3I0 for 12s and the disconnected phase current is less than 0.06In (In is the secondary rated current), and no component trips, the alarm TA is disconnected. This alarm does not lock the outlet power. After the TA is disconnected, the zero sequence current and the low current local criterion are exited.

CSC300

TV disconnection

(1) Voltage balance TV abnormality discrimination When there are two sets of TVs on the mobile terminal, the voltage balance principle is used to discriminate between the two groups of TVs. The voltage balance type TV abnormality discriminant principle is used to compare the voltages of the secondary side of two groups of TVs (machine-side ordinary TV1 and longitudinal daytime TV2). When a TV secondary side loses voltage, the relay acts, and the disconnection is issued after 10s delay. signal.

(2) TV abnormality discrimination when there is only one set of TVs on the machine side When there is only one set of machine-side ordinary TVs (accessed by corners), the following method is used to determine:

1) The three line voltages are all less than 20V, and any phase current is greater than 0.1A (TA secondary rated current is 1A) or any phase current is greater than 0.3A (TA secondary rated current is 5A), used to detect three phases Broken wire or two-phase broken wire;

2) When there is a negative sequence voltage and no negative sequence current, it is used to detect a phase disconnection. When a TV abnormality is detected, a 10 s delay signal is issued and the corresponding protection is blocked according to the user's needs.

(3) The principle of abnormal TV discrimination on the high-voltage side of the main transformer and the low-voltage side of the high-voltage plant and the low-voltage side of the main transformer are as follows:

1) The three-phase voltage is less than 18V, and any phase current is greater than 0.1A (TA secondary rated current is 1A) or any phase current is greater than 0.3A (TA secondary rated current is 5A), used to detect three-phase loss Pressure

2) The vector sum of the three phase voltages (self-produced 3U0) is greater than 18V, and the difference between any two phase voltages of any one of the phases is greater than 18V (used to distinguish the grounding system of the small current grounding point), detecting one phase or Two-phase disconnection;

3) The vector sum of the three phase voltages (self-produced 3U0) is greater than 90V, and the three line voltages are all less than a certain value (internal fixed) for detecting the two-phase disconnection when the TV loop has a parallel branch. When a TV abnormality is detected, a 10 s delay signal is issued and the corresponding protection is blocked according to the user's needs.

TA disconnection

Under normal circumstances, it is judged that the TA disconnection is determined by checking that one of the phases of the currents has no current and there is a differential current, that is, it is judged as a TA disconnection. When there is a sudden change in current, the criterion is as follows: 1) The current decreases (instead of increasing) after the mutation; 2) There is no phase in the three-phase current of the current side, and there is no change in the current of the opposite side; That is, it is judged as a TA abnormality, and when a TA abnormality is detected, an alarm signal is issued. At the same time, according to the needs of users, the corresponding protection is blocked.

CSC150

TV disconnection

TV disconnection discrimination The neutral line grounding system TV disconnection criterion is:

(1) Three-phase TV disconnection: the three-phase bus voltage is less than 8V and the branch currents running on the bus are not all 0;

(2) Single-phase or two-phase TV disconnection: self-produced 3U0 is greater than 7V. The TV disconnection criterion for the small current grounding system is:

(1) Three-phase TV disconnection: the three-phase bus voltage is less than 8V and the branch currents running on the bus are not all 0;

(2) Single-phase TV disconnection: self-produced 3U0 is greater than 7V and one of the difference between the two voltage values ​​of the line voltage is greater than 18V;

(3) Two-phase TV disconnection: self-produced 3U0 is greater than 7V and all three line voltages are less than 7V. For 10s, the above criteria are used to determine the bus disconnection of the bus. After the TV is disconnected, the voltage blocking component automatically switches the voltage loop and sends an alarm signal, but does not lock the protection.

TA disconnection

Bus-coupled CT disconnection: large differential differential current balance I mother differential differential current imbalance II mother differential differential current imbalance I, II mother differential differential current sum balance;

WFB800

TV disconnection

Criterion 1: Voltage balance TV disconnection discrimination

The voltage-balanced TV disconnection discriminates and compares the voltages on the secondary side of the two sets of voltage transformers. When a certain TV loses voltage, the relay acts, and the disconnection signal criterion is instantaneously issued. 2: Single-group voltage transformer TV without zero-sequence voltage is broken. Line discrimination a. The difference between the absolute values ​​of the two arbitrary phases is greater than 18V and the three-phase current is less than Iset; (single-phase, two-phase disconnection) b. The three-phase voltage is less than 8V, and any phase current is greater than 0.06 times the rated current, The three-phase current is less than Iset; (three-phase disconnection) After all the above conditions are met, the TV disconnection signal is delayed by 80ms; the zero-sequence voltage type single-group voltage transformer TV disconnection is judged a. |• aU+• bU+• cU-K*3• 0U|>18V Three-phase current is less than Iset; (single-phase, two-phase disconnection) When the grounding mode is 1, k=0.5773; when the grounding mode is 0, it is not directly grounded, k=1.732. b. The three-phase voltage is less than 8V, and any phase current is greater than 0.06 times the rated current, and the three-phase current is less than Iset; (three-phase disconnection) After any of the above conditions are met, the TV disconnection signal is delayed by 80ms. Criterion 4: a. The positive sequence voltage is less than 30V, the three-phase current is greater than 0.06 times the rated current; b. The negative sequence voltage is greater than 8V. After satisfying any of the above conditions, the TV disconnection signal is delayed by 10s. This criterion is only used for signaling and is not used for protection blocking criteria.

TA disconnection

When any phase differential current is greater than 0.15 times the rated current, the TA disconnection discriminating procedure is started, and the following conditions are considered to be that the TA is disconnected: a. At least one phase current of the three-phase current of the current side is zero b. At least one phase current is constant; c. The maximum phase current is less than 1.2 times the rated current.

WXH801

TV disconnection

There are two criteria for detecting TV disconnection in the device longitudinal, distance, zero sequence protection and reclosing. Both criteria have a delay of 1s, and only when the line is running normally, the starting component does not start and sums itself. When the control word is input, the input is turned on. Once the start-up component is started, the TV disconnection detection is immediately stopped, and the input is resumed after the entire group is reset. 1) The sum of the three-phase voltages is not zero and is used to detect one-phase or two-phase disconnection. The criterion is: |UA+UB+UC|>7V (effective value) 2) Three-phase voltage loss detection three-phase voltage loss criterion: the three-phase voltage RMS is lower than 8V, and any phase current is greater than 0.04In or The three-phase currents are all less than 0.04In and no trip position is opened.

TA disconnection

When the TA is disconnected, the zero sequence current will exist for a long time. The longitudinal, distance and zero sequence protection will drive the alarm II relay to send local and central alarm signals when the zero sequence current lasts 12S is greater than the zero sequence auxiliary start setting I04. TA loop abnormal alarm report, blocking protection, the device continues to monitor the zero sequence current, once the zero sequence current disappears, the protection will automatically release the lock.

WMH800

TV disconnection

Large ground current system: When any phase voltage is lower than the PT disconnection setting, or the self-produced zero sequence (3U0) or negative sequence (3U2) voltage is greater than 7V, the delay is 7s to send a "PT disconnection" signal. Small ground current system:

The composite voltage blocking component has three line low voltage components and one negative sequence voltage (3U2) component for each bus bar, and each component works in parallel to form an OR gate relationship.

TA disconnection

When the system is running normally, the difference is poor and the busbars of each segment are balanced. When the differential current exceeds the limit of CT disconnection for 7s, it is judged as CT.

Broken line

The lock disconnection phase of the section of the bus differential protection concurrently "CT disconnection" signal.

BP2B

TA disconnection

The difference current is greater than the fixed value of the TA disconnection. The delay is 9 seconds to send the TA disconnection alarm signal, and the busbar protection is blocked. After the current loop is normal, it will automatically resume normal operation in 0.9 seconds.

PSL600

TV disconnection

When using bus PT

When the sum of the absolute values ​​of the three-phase voltage is less than

0.5Un is considered to be PT

Three-phase voltage loss when using line PT

When the sum of the absolute values ​​of the three-phase voltage is less than

0.5Un

The switch is not in the jump position

TWJA TWJB and TWJC

No action or a phase current is greater than

0.04In is considered to be PT

Three-phase loss of pressure

Set the PT when the above conditions are met

Three-phase voltage loss flag delay 100ms

Blocking high frequency protection and distance protection 1.25s PT disconnection signal and PT

Three-phase voltage loss event Whether it is PT asymmetric disconnection or PT three-phase pressure loss is regarded as PT

Broken line

TA disconnection

The zero sequence difference current is used to identify the CT disconnection, the zero sequence current difference on both sides is greater than the fixed value, and the current of the largest phase of the differential current is less than the predetermined threshold value.

DGT801

TV disconnection

Voltage-balanced TV disconnection, can be used for zero-sequence voltage stator turn-to-turn protection and stator grounding protection TV TV disconnection discrimination when TV is disconnected once. It is based on the principle of amplitude and phase relationship of the phase-to-phase voltages of the two TVs of the comparison machine. When the differential pressure abUΔ or bcUΔ or caUΔ is greater than the setting value, and the ordinary TV has no negative sequence voltage, the device is judged as a dedicated TV once disconnected. , to lock the inter-turn protection; and when the pressure difference is greater than the set value, the ordinary TV secondary negative sequence voltage is greater than the set value, the device is judged as ordinary TV disconnection, de-locking sub-ground protection, etc. to protect the ordinary TV voltage

TA disconnection

The one-phase differential action has no negative sequence voltage, that is, it is determined that the TA is disconnected. This is because the neutral point of the generator is not directly grounded, and the internal phase-to-phase short circuit generally has two-phase differential or three-phase differential simultaneous action.

1) The current is increased when the short circuit is normal, and the current is reduced when the line is broken. The current mutation direction is negative as the main criterion.

(2) Generally, the possibility of simultaneous disconnection of the opposite side TA is not considered, so a sudden change in current must occur on the same side TA.

(3) Do not consider the simultaneous disconnection of three phases, that is, the sudden current does not exceed 2 channels.

(4) At least one side of the three-phase current is sound, the TA disconnection side current must have one phase, and the other phase or two phases are small.

(5) The differential current should be less than the Ict setting value of the differential current multiple of the TA disconnection function.