Request

Ensure that this Instruction Manual is delivered to the end users and the maintenance manager.

1 JEP0-IL9554

－

Safety precautions

－

Before installation, operation, maintenance, and inspection, please be sure to read this instruction manual and all other attached documents thoroughly in order to work safely with the equipment. Please ensure that you fully understand the equipment, safety information, and precautions that need to be taken before working with the equipment. Safety precautions are classified as “Caution.”

Caution

The case where a dangerous situation can arise and there is the possibility that moderate or minor injuries can occur, or property damage can take place if the equipment is handled incorrectly.

Furthermore, even with items described as Caution, there is the possibility of serious consequences depending on the situation. All of the described contents are important. Therefore, be sure to comply with them.

Caution

1.

Installation and Wiring work

Caution

＊ Ensure that the equipment is mounted and connected correctly. Otherwise, there are risks of failure, burning, or maloperation.

＊ Securely tighten the terminal connection screws. Otherwise, there are risks of failure and burning.

For tightening torque of screws, refer to the following Table.

Material

Nominal dia.

Standard value of torque

Allowable range

Steel M3.5

1.10N

・ m

（ 11.2kgf

・ cm ） （

0.932

9.5

～

～ 1.27N

12.9kgf

・

・ m cm ）

Place of use

Terminal block

Steel

Steel

Steel

Brass

M4

M6

M10

M4

1.65N

・ m

（ 16.8kgf

・ cm ）

5.49N

・ m

（ 56kgf ・ cm ）

26.5N

・ m

（ 270kgf ・ cm ）

0.961N

・ m

（ 9.8kgf

・ cm ）

（

（

1.39

14.2

（

4.71

（ 48

22.6

230

0.824

8.4

～

～

～

～

～

～

～

1.89N

19.3kgf

6.37N

65kgf

～

・

30.4N

310kgf

11.3kgf

・

1.11N

・

・

・

・

・

・ m cm m cm ） m cm m cm

）

）

）

Drawer fixing screw of unit-drawer type

(RD type)

Fixing screw for mounting

MPD-3C bottom screw

MZT primary terminal (k, ℓ)

MPD-3T terminal

＊ The equipment must be correctly grounded using the designated grounding terminals where they exist. Failure to do so may lead to the risk of electric shock, equipment failure, malfunction or failure to operate.

＊ Ensure that the equipment is connected correctly in accordance with the details (e.g.: polarity or phase sequence) shown on the connection terminals. Otherwise, there is the risk of failure, burning, malfunction, or maloperation.

＊ All power supplies and transformers to the equipment must be of suitable capacity and rated load to avoid the risk of malfunction and maloperation.

＊ Be sure to return all terminal covers, protection covers to their original positions once any work is complete. If they remain uncovered there is a risk of electrical shock.

＊ The appropriate connectors must be used to ensure compatibility with the connector terminals to avoid the risks of failure or fire.

＊ When inserting subunit into the case, please ensure that there is no gap between front side of the subunit and the case.

In addition, tighten lower screw surely. If the subunit is inserted inadequately, there are risks of malfunction or generation of heat.

2.

Operating and Setting

The equipment must be used within the following range limits. Otherwise, there is a risk of reducing the performance and life of the product.

・ Variation range of auxiliary power supply voltage Within –15 to +10% of the rated voltage

・ Frequency variation Within ±5% of the rated frequency

・ Ambient temperature

・

・

Relative humidity

Altitude

–20 to +60 ℃

(under the state where dew condensation or freezing does not occur)

30 to 80% on daily average

2000m or lower

・ The state where abnormal vibration, shock, inclination, magnetic field( ※ ) are not applied

・ The state where it is not exposed to harmful smoke/gas, saline gas, water droplet or vapor, excessive dust or fine powder, explosive gas or fine powder, wind & rain

( ※ ) If there is a large amount of current on main circuit surrounding the relay, the operation indicator may be magnetized and turned from black to orange color. In that case, please shield back of the relay by iron plate.

2 JEP0-IL9554

Caution

＊ The equipment must only be operated and handled by qualified personnel. Otherwise, there are risks of electric shock, injury, failure, malfunction, and maloperation.

＊ Handling and maintenance of the equipment must only be carried out after gaining a thorough understanding of the instruction manual. Otherwise, there is the risk of electric shock, injury, failure, malfunction, or maloperation.

＊ While energized, do not remove any components other than those which have been designated. Otherwise, there is a risk of failure, malfunction, or maloperation.

＊ While energized, do not draw out the internal unit (subunit). Otherwise, there is a risk of electric shock, injury, failure, malfunction, or maloperation.

＊ When changing the setting value during the energized state, ensure that all trip circuits are locked in order not to operate.

Otherwise, there is a risk of malfunction.

＊ Use in rated range. Otherwise, there is a risk of malfunction.

3.

Maintenance and Inspection

We recommend that any tests or inspections are carried out under the following conditions, as well as any additional conditions described in the instruction manual.

・ Ambient temperature

・ Relative humidity

20±10 ℃

90% or less

・ External magnetic field

・ Atmospheric pressure

・

・

Mounting angle

Frequency

・ Waveform (in the case of AC)

80A/m or less

86 ～ 106×10 3 Pa

Regular direction ±2°

Rated frequency ±1%

・ AC component (in the case of DC)

Distortion factor: 2% or less

Effective value of higher harmonics only

Distortion factor ＝ ────────────────────────────── ×100(%)

Effective value of fundamental wave

Ripple factor: 3% or less

Max. value – Min. value

Ripple factor ＝ ─────────────────────── ×100(%)

Average value of DC

Caution

・ Auxiliary power supply voltage Rated voltage ±2%

＊ The equipment must only be operated and handled by qualified personnel. Otherwise, there are risks of electric shock, injury, failure, malfunction, and maloperation.

＊ Handling and maintenance of the equipment must only be carried out after gaining a thorough understanding of the instruction manual. Otherwise, there is the risk of electric shock, injury, failure, malfunction, or maloperation.

＊ When replacing the equipment, use a product of same model, rating, and specifications. Otherwise, there is the risk of failure or fire.. If any other product is to be used, the manufacturer must be consulted.

＊ Do not exceed the overload capacity for voltage and current. Otherwise,equipment failure or fire could occur.

＊ Do not touch any live parts, such as terminals, etc. Otherwise, there is a risk of electric shock.

＊ Do not clean the equipment while energised. When the cover needs to be cleaned, make use of a damp cloth.

4.

Transportation

＊ Transport the equipment in the correct orientation.

＊ Do not apply excessive shock and/or vibration as this could affect the performance and life of the product.

5.

Storage

The storage environment shall comply with the following conditions. Otherwise, there is a risk of reducing the performance and life of the product.

・ Ambient temperature –20 to +60 ℃

・ Relative humidity

(under the state where dew condensation or freezing does not occur)

30 to 80% on daily average

・ Altitude 2000m or lower

・ The equipment must not be exposed to abnormal vibration, shock, inclination, or magnetic fields.

・ The equipment must not be exposed to harmful smoke/gas, saline gas, water droplets or vapor, excessive dust or fine powder, explosive gas or fine powder, wind & rain.

6.

Repair and Modification

＊ When carrying out repair and/or modification, please consult with the manufacturer in advance. We will not take any responsibility for any repair and/or modification (including software) which has been carried out without prior consent.

7.

Disposal

Disposal must take place in accordance with the applicable legislation

3 JEP0-IL9554

Guarantee

1.

Guarantee period

The guarantee period of this product should be one year after delivery, unless otherwise specified by both parties.

2.

Scope of guarantee

When any fault or defect is detected during the period of guarantee and such fault or defect is proved to be caused apparently at the responsibility of MITSUBISHI ELECTRIC CORPORATION, the defective unit concerned will be repaired or replaced with substitute with free of charge. However, the fee for our engineer dispatching to site has to be covered by the user. Also, site retesting or trial operation caused along with replacing the defect units should be out of scope of our responsibilities.

It is to be acknowledged that the following faults and defects should be out of this guarantee.

(1) When the faults or defects are resulted from the use of the equipment at the range exceeding the condition/environment requirements stated in the catalogue and manual.

(2) When the faults or defects are resulted from the reason concerning without our products.

(3) When the faults or defects are resulted from the modification or repair carried out by any other entity than

MITSUBISHI ELECTRIC CORPORATION.

(4) When the faults or defects are resulted from a phenomenon which cannot be predicted with the science and technology put into practical use at the time of purchase or contract

(5) In case of integrating our products into your equipment, when damages can be hedged by the proper function or structure in the possession of your equipment which should be completed according to the concept of the de fact standard of industry.

(6) In case of that the faults or defects are resulted from un-proper application being out of instruction of

MITSUBISHI ELECTRIC CORPORATION.

(7) In case that the faults or defects are resulted from force majeure such a fire or abnormal voltage and as an act of God such as natural calamity or disaster.

3.

Exclusion of loss in opportunity and secondary loss from warranty liability

Regardless of whether in guarantee period or not, MITSUBISHI ELECTRIC CORPORATION shall not be liable for compensation of damages caused by any cause found not be the responsibility of MITSUBISHI

ELECTRIC CORPORATION, loss in opportunity, lost profits incurred to the user by failures of MITSUBISHI

ELECTRIC CORPORATION products, special damages and secondary damages whether foreseeable or not, compensation for accidents, and compensation for damages to products other than MITSUBISHI ELECTRIC

CORPORATION products and other tasks.

4.

Applications of products

(1) The user is requested to confirm the standards, the regulations and the restrictions which should be applied, in case of utilizing this product and another one in combination. Also, the user is requested to confirm the suitability of our products to your applied system or equipment or apparatus by yourself. MITSUBISHI

ELECTRIC CORPORATION shall not be liable for any suitability of our products to your utilization.

(2) This product has been designed and manufactured for application in general industries, etc. Thus, application in which the life or an asset could be affected by special application such as medical system for life-sustaining, in nuclear power plants, power plants, aerospace, transportation devices (automobile, train, ship, etc.) shall be excluded from the application. In addition to above, application in which the life or an asset could be affected by potentially chemical contamination or electrical interference and also in which the circumstances and condition are not mentioned in this manual shall be excluded from the application.

Note even if the user wants to use for these applications with user’s responsibility, the user to be requested to approve the specification of MITSUBISHI ELECTRIC CORPORATION products and to contact to the technical section of MITSUBISHI ELECTRIC CORPORATION prior to such applications. If the user applies

MITSUBISHI ELECTRIC CORPORATION products to such applications without any contact to our technical section, MITSUBISHI ELECTRIC CORPORATION shall not be liable for any items and not be insured, independently from mentioned in this clause.

(3) In using this product, the working conditions shall be that the application will not lead to a major accident even if any problem or fault occur, and that backup or duplicate system built in externally which should be decided based on the importance of facility, is recommended.

(4) The application examples given in this manual are reference only and you are requested to confirm function and precaution for equipment and apparatus and then, use our products.

(5) The user is requested to understand and to respect completely all warning and caution items so that unexpected damages of the user or the third party arising out of incorrect application of our products would not be resulted.

4 JEP0-IL9554

5.

Onerous repair term after discontinuation of product

(1) MITSUBISHI ELECTRIC CORPORATION shall accept onerous product repairs for 7 years after production is discontinued. (However, the product which was made over 15 years is recommended to replace.)

(2) Product supply (including repair parts) is not available after production is discontinued.

6.

Changes in product specification

The specification given in the catalogue, manuals or technical documents are subject to change without prior notice.

7.

Scope of service

The technical service fee such as engineer dispatching fee is excluded in the price of our products.

Please contact to our agents if you have such a requirement.

5 JEP0-IL9554

MDG-A3 Series Directional Earth Fault Relay [Standard: JIS C 4609 (1990)]

Features

1. Directional earth fault relay for MPD-3 type ZVT correspondence.

2. Wide setting range and fine setting steps enable flexible protection coordination.

3. The number of connectable relay units to MPD-3 type

ZVT is increased to 20.

Caution However, this increase is limited only when all of the relays are composed of New MELPRO-A series. If another series are combined, the number of connectable units is limited to 5.

4. Max. 20 relays can be connected through V0 extension terminal.

5. Reset method of output contacts can be switchable between auto-reset and self-hold.

6. The fault value record function is installed.

7. Good operability and visibility design is adopted.

The numerical display turns on for 3 seconds when the setting value is changed, which enables to check setting values easily.

8. Panel cutout is the same as previous MELPRO-A series and E series.

Ratings and Specifications

Ratings

Settings

Type name

Style No.

Zero-sequence current

Zero-sequence voltage

Frequency

Auxiliary power supply

I

0

Operation value

V

0

Operation value

Operating time

Using condi tion

Frequency

Output contact

Max. sensitivity angle

Self-monitoring

Operation indicator

MDG-A3V-R

104PGA

0.2A (MZT type ZCT primary)

7V (MPD-3 type ZVT secondary)

MDG-A3V-RD

519PGA

50/60Hz (switchable)

AC110V (Range: 90 ～ 120V)

0.1

(*) -0.2-0.4-0.6-0.8-1.0A (ZCT primary value)

LOCK

(*)

-2-2.5-3-4-5-6-7-7.5-8-9 – 10%

(Single-phase fault in 6.6kV power systems:

V

0

primary = 3810V, ZVT secondary = 7V)

Instantaneous

Lead 10

(*)

°

-0.2-0.3-0.4-0.5-0.6-0.7-0.8-0.9-1.0s

50Hz(SW1-ON) - 60Hz

Self-hold(SW2-ON)

(SW3-ON)

–

–

(*) (SW1-OFF)

Auto-reset

Lead 45 °

(*)

(*)

(SW2-OFF)

(SW3-OFF)

The "RUN" indicator (green-color) is lighted in normal condition.

The indicator turns from black into orange color when the protection element is put into operation. (Manual resetting type)

Display

Numerical display

Indication item

V

0

measurement

Range

1.0

～ 12.0%

0.05

～ 0.09A, 0.1

～ 1.5A I

0

measurement

Phase measurement

V

0

, I

0

Pickup

V

0

setting

0 ～ 359 ° (V

0

standard, I

0

lag display)

U.-I.

Lo.

( ※ 1)

,2.0

～ 10%

I

0

setting 0.1

～ 1.0A

Operating time setting In.

( ※ 2)

,0.2

～ 1.0s

Condition setting

Frequency, output contact, and max. sensitivity angle are shown at intervals of 2 seconds.

2.0

～ 40.0% Fault record of V

0

Fault record of I

0

0.1

～ 1.5A

Fault record of phase 0 ～ 359 ° (V

0

standard, I

0

lag display)

Clear fault record O.K.

TEST (Forced operation) F.O.

※ 1 "Lo." means LOCK setting (the protection element is locked).

※ 2 "In." is the display for instantaneous setting.

6 JEP0-IL9554

Number of relay connection

Test button

(Forced operation)

Power consumption (Power supply)

Case

(Munsell color)

Max. 20 relays can be connected through V

0

extension terminal (M-N) of the relay which is directly connected to MPD-3 type ZVT.

By turning the indicator select switch to "TEST" and pushing "TEST" button for 2 seconds or more, output contact can be forced to operate (except for the case of LOCK setting).

Normal ： 3.0VA Operating ： 4.0VA

Unit-fixed type Unit-drawer type

(Fig. 2-11)

(0.6B7.6/0.2)

(Fig. 2-12)

(0.6B7.6/0.2)

Approx. 0.6kg Approx. 0.7kg Mass

(*) shows factory setting.

Note) It is necessary to combine MZT type ZCT and MPD-3 type ZVT with MDG-A3V relay.

Don't combine other transformers with this relay.

Application to 3.3kV system voltage:

The MPD-3 type ZVT is intended for use at 6.6kV system voltage.

When applied to a system voltage of 3.3 kV, ZVT secondary output voltage at single-phase fault is 3.5V.

(Half of the rating voltage (7V) at 6.6kV system.)

Therefore, setting and measurement display are as follows:

Example 1) In the case of 10% setting for 3.3kV system, the actual setting value should be 5%, which is half of 10%.

Example 2) When the V

0

measurement display is 5%, the actual value in 3.3kV system is 10% of the single-phase fault, which is twice the displayed value.

7 JEP0-IL9554

Characteristics

(MDG-A3V type relay ＋ MZT type ZCT ＋ MPD-3 type ZVT combination)

Item

Standard use conditions

Operation value characteristics

I

0

V

0

Characteristics

Ambient temperature: – 20 to +60 ℃ (Under the state where dew condensation or freezing does not occur)

Relative humidity: 30 to 80% on daily average

Altitude: 2000m or lower

・ The state where abnormal vibration, shock, and inclination are not applied.

・ The state where it is not exposed to harmful gas, excessive dust, and water droplet or vapor.

Setting: Zero-sequence voltage V

0

= 2%, Operating time T = Instantaneous

Input: V

0

= 150% of setting value

Criteria: Within ± 10% of each setting current at the maximum sensitivity angle

Setting: Zero-sequence current I

0

= 0.1A, Operating time T = Instantaneous

Input: I

0

= 150% of setting value

Criteria: Within ± 25% of each setting voltage at the maximum sensitivity angle

V

0

setting (%) 2 2.5 3 4 5 6 7 7.5 8 9 10

MPD-3C primary (V) 76.2 95.3 114.3 152.4 190.5 228.6 266.7 285.8 304.8 342.9 381

T terminal (V) 7.62 9.53 11.43 15.24 19.05 22.86 26.67 28.58 30.48 34.29 38.1

Reset value characteristics

Phase characteristics

90% or more of operating value (Both I

0

and V

0

)

Setting: Zero-sequence current I

0

= 0.1A, Zero-sequence voltage V

0

= 2%, Operating time T = Instantaneous

Input: I

0

= 1000% of setting value, V

0

= 150% of setting value

I

0

operating area (V

0

standard):

Max. sensitivity angle Max. sensitivity angle

Phase setting

45 ° 10 °

Lag 45 °± 20 ° 80 °

+5 °

-30 °

Lead 135 °± 20 °

+30 °

100 °

-10 °

Max. sensitivity angle 45 °

(For non-grounding system)

0 °

Lead ←

V

０

→ Lag

25 °

90 °

115 °

Operation area

155 °

65 °

90 °

0.2 0.4 0.6 0.8 1.0A

Non-operation area

90 °

Max. sensitivity angle 10 °

(For reactor grounding system)

0 °

Lead ←

V

０ → Lag

Operation area

130 °

50 °

85 °

90 °

0.2 0.4 0.6 0.8 1.0A

Non-operation area

Operating time characteristics

180 ° 180 °

Input: V

0

= 0 → 150% of setting value, I

0

= 0 → 130% and 400% of setting value

(at the maximum sensitivity angle)

Time setting

Current Ratio to the setting current

130% 400%

Instantaneous

0.2s

50 ～

0.1

100ms

～ 0.3s

50 ～

0.1

100ms

～ 0.2s

0.3s or more ± 20% of setting time ± 10% of setting time

Resetting time characteristics

Overshoot time characteristics

High ground fault current characteristics

Input: V

0

= 150% of setting value → 0, I

0

= 130% and 400% of setting value → 0

Criteria: 250ms ± 50ms

Setting: Zero-sequence current I

0

= 0.1A, Zero-sequence voltage V

0

= 2%, Operating time T = 0.2s

Input: I

0

= 400% of setting value, V

0

= 150% of setting value (at the maximum sensitivity angle)

Applied time: 0.05s

Criteria: The relay shall not operate.

Setting: Zero-sequence current I

0

= 0.1A, Zero-sequence voltage V

0

= 2%, Operating time T = Instantaneous

Input: V0 = 3810V (MPD-3C primary), I0 = 30A (MZT primary)

Criteria: At the lead angle of 90 ° (V

0

standard), the relay shall operate.

At the lag angle of 90 ° (V

0

standard), the relay shall not operate.

(Note) When the max. sensitivity angle is set to 10°and this product is applied to a system with ground fault current exceeding 25A, use MZT-77D type or MZT-112D type ZCT.

8 JEP0-IL9554

Variation characteristics of auxiliary power supply voltage

Input: Auxiliary power supply = AC90V ～ AC120V

Criteria: Within ±10% of I

0

and V

0

operation values at rated voltage

Temperature characteristics

Vibration

Ambient temperature: -20, +60 ℃

Criteria:

Operation values of I

0

and V

0

: Within ± 20% of operation values at 20 ℃

Operating time: Within ± 20% of operating time at 20 ℃

Phase characteristics: Within ± 15 ° of operating phase at 20 ℃

Frequency

(Hz)

10

16.7

Peak-to-peak amplitude mm

(Acceleration m/s 2 )

Forward/ backward

Right/left Up/down

5 (10)

0.4 (2)

2.5 (5)

Vibration time

(s)

30

600

Setting: Minimum operation value and minimum operating time

Input: Rated auxiliary power supply

I

0

and V

0

= 0

Criteria: No malfunction and no abnormal indication

Shock

Insulation resistance

Withstand voltage

Lightning impulse withstand voltage

Noise-proof

Radio disturbance

Contact capacity

Maximum acceleration: 300m/s 2

Direction: 3 directions in forward/backward, right/left, and up/down

Criteria: No abnormality when applying two shocks in each direction

Test circuit: Between all circuits and earth (E terminal), between separate circuits (except for I

0

-V

0 circuits), and between the poles of contacts

Criteria: More than 10M Ω by DC500V megger.

(Note) The test is held under the condition that relative humidity is less than 80%.

Between all circuits and earth (E terminal): AC2000V, for 1 minute

Between separate circuits (except for I

0

-V

0

circuits): AC2000V, for 1 minute

Between the poles of contacts (a11-a12, a21-a22): AC1000V for 1 minute

Apply standard waveform (1.2/50 μs) to positive/negative pole for 3 times respectively.

Between ZVT/ZCT primary and earth: 60kV

Between all circuits of the relay and earth (E terminal): 4.5kV

Between ZVT/ZCT secondary and control circuit: 4.5kV

Between contact terminal and power supply terminal: 3.0kV

Between terminals of power supply: 3.0kV

Apply damped oscillatory wave prescribed in JIS C 4609 for 2 seconds.

・ Between ZVT/ZCT secondary and earth (E terminal)

・ Between power supply terminal and earth (E terminal)

・ Between terminals of power supply

・ Between contact terminal and earth (E terminal)

Setting: Minimum operation value and minimum operating time

Input: Rated auxiliary power supply, I

0

and V

0

= 0

Criteria: No malfunction

Intermittently irradiate radio waves to the front panel of the relay with a transceiver of 150MHz or 400MHz band (5W output) from a distance of 0.5m.

Setting: Minimum operation value and minimum operating time

Input: Rated auxiliary power supply, I

0

and V

0

= 0

Criteria: No malfunction

Making

(Closing)

DC110V 15A (L/R=0ms)

DC220V 10A (L/R=0ms)

AC110V 10A (cosφ=0.1)

Breaking

(Opening)

DC110V 0.3A (L/R=7ms)

AC110V 5A (cosφ=0.1)

AC220V 1A (cosφ=0.1)

Note) For details, refer to JIS C 4609 (1990).

Internal connection diagram

※ RD-type has shorting bar in I

0

circuit.

Y1

V

0 in

Y2

V

0

Level assessment

Z1

I

0 in

Z2

Directional assessment

I

0

Level assessment

P1

Auxiliary power supply

P2

Operation indicator

M

V

0 out

N

Power supply

RUN indicator

X0

Output contact

X0

X1

Output contact

X1 a11

Output contact a12 a21

Output contact a22

E

Continuous monitoring

Power circuit monitoring

Fig. 2-1 Internal connection diagram

9 JEP0-IL9554

Structure

RUN indicated LED (Green)

It shows the result of selfmonitoring. It lights up in normal condition.

Numerical display LED

Following item is displayed by indicator select switch setting.

・ V

0

, I

0

, and phase measurement

・ V

0

, I

0

pickup

・ Setting value

・ Fault record

・ Clear fault record

・ Forced operation (test)

Test button

By turning the indicator select switch to "TEST" and pushing

"TEST" button for 2 seconds or more, output contact can be forced to operate (except for the case of LOCK setting).

CPU reset button

While this button is pressed, the relay function is locked and the RUN indicated LED is turned off. In addition, the output contact is reset from self-hold state.

Indicator select switch

The numerical display shows according to this selection switch. Don't leave this switch with halfway state.

Setting switches for operation value and time

Set the setting values. The black part is equal to maximum value, but the numerical display is turned off.

Don't leave the switches with halfway state.

Operation indicator reset lever

Move this lever up and down, then the operation indicator resets.

(Note) Don't pull the lever strongly.

Setting switches for using condition

Don't use any tool with a sharp point when the switches are set.

(It may cause damage to the switch lever.)

SW1 Frequency

ON

OFF

50Hz

60Hz

Output contact

Self-hold (Ho.)

Auto-reset (FU.)

SW2

ON

OFF

SW3 Max. sensitivity angle

ON

OFF

Lead 10

Lead 45

°

°

Factory settings are set to a default of OFF.

Operation indicator

The indicator turns from black into orange color when the protection element is put into operation.

Fig. 2-2 Structure of MDG-A3 series (front view)

10 JEP0-IL9554

Operating Description

1. Protection function

① The power supply can be derived from VT secondary.

② Set using condition switches according to your using condition (frequency, output contact, and max. sensitivity angle).

③ Zero-sequence voltage input is supplied from secondary output of MPD-3 type ZVT combined with the relay. This input is transmitted to V

0

expanded output terminals (M-N).

④ Zero-sequence current input is supplied from secondary output of MZT type ZCT combined with the relay.

⑤ If both zero-sequence current and zero-sequence voltage is greater than or equal to the setting value, and if the phase difference between them is within the operating area, the operation timer starts. The relay actuates the output contact and operation indicator after a preset time of the operation timer.

⑥ After the relay operation, if zero-sequence current or zero-sequence voltage falls below the setting value, or if the phase difference between them is out of the operating area, the output contact will be in the state set by the using condition setting switch (auto-reset or self-hold).

The operation indicator keeps the operation status

(orange color). To reset the indicator, move the reset lever up and down.

2. RUN display (Self-monitoring function)

This relay monitors control voltage, electric circuit, and program data at all time. The RUN LED

(green) lights up in the normal condition.

In the abnormal condition, the RUN LED goes out and the error message Ｅ ｒ ｒ is displayed on the numerical display LED, with the output contact locked.

3. Numerical display function

By switching the position of the indicator select switch, following items can be displayed on the numerical display LED.

① V

0

voltage measurement

The display shows the value of zero-sequence voltage. The display range is from 1.0% to 12.0%.

(If input voltage is less than 1.0%, the display goes out. If input voltage is more than 12.0%, the error message Ｏ .

Ｆ . is displayed.)

Here, "100%" denotes complete single-phase fault in 6.6kV power systems: V

0

primary = 3810V, ZVT secondary = 7V.

This function makes it possible to measure the residual V

0

voltage in sound condition.

② I

0

current measurement

The display shows the value of zero-sequence current. The display range is from 0.05A to 1.5A.

(If input current is less than 0.05A, the display goes out. If input current is more than 1.5A, the error message Ｏ .

Ｆ . is displayed.)

③ Phase measurement

The display shows the phase of zero-sequence current relative to the zero-sequence voltage.

The display range is 0 ° to 359 ° (lag).

④ V

0

, I

0

pickup

When input zero-sequence voltage and zero-sequence current exceeds setting value, Ｕ .

－ Ｉ . is displayed.

(V

0

pickup: Ｕ .

－ , I

0

pickup: －Ｉ .)

When the indicator select switch is set to "PICKUP",

－ is displayed.

This function can be used for operation value tests.

⑤ Setting value

It displays the setting condition of the relay including V

0

value, I

0

value, and operating time setting.

⑥ Using condition

When the indicator select switch is set to

"CONDITIONS", the using condition settings of frequency, output contact, and maximum sensitivity angle are sequentially displayed at approximately

2 second intervals in accordance with the setting switches of SW1 to SW3.

For example, the settings are 50Hz, Self-hold, and

Lead 10 ° , the display shows "50", "Ho.", and "10" sequentially.

For another example, the settings are 60Hz, Autoreset, and Lead 45 ° , the display shows "60", "FU.", and "45" sequentially.

4. Fault record function

① Display of fault records

When a fault occurs, the relay outputs the operating signal, and at the same time the input values of zero-sequence voltage, zero-sequence current and phase are recorded. When the indicator select switch is set to the position of each fault record, the records are displayed starting from the latest record to the oldest one at approximately 2 second intervals. The relay can save the newest five phenomena.

The records are saved in the non-volatile memory, therefore the records can be read again after shutting the power off.

Note that the fault record may not be saved if the auxiliary power supply is turned off soon after the relay operation.

② Clearing of fault records

Set indicator select switch to "CLEAR FAULT REC." and hold for 5s or more, then Ｏ .

Ｋ . is displayed and all of the fault record are cleared.

5. Display function of setting change

When a setting is changed, the setting value after changing is displayed for approx. 3s preferentially.

11 JEP0-IL9554

Application example

a) Single circuit

ZCT

“ MZT ”

3

MDG-A3V b) Multiple circuits (Directly supply V

0

from MPD-3 type ZVT)

MDG-A3V

ZCT

“ MZT ”

”

3

PCT

DS

ZVT

“ MPD-3 ”

PCT

DS

CB

CB

“

ZVT

MPD-3 ”

CB

ZCT

“ MZT ”

3

CB

MDG-A3V

ZCT

“ MZT ”

3

MDG-A3V

The number of MDG-A3V and MVG-A3V relay which can be directly connected from MPD-3 type ZVT is up to 20. However, previous models

(e.g. MDG-A1V or MVG-A1V relay) or another series (e.g. MELPRO-D/S series) are combined, the number of connectable relays is limited to 5. c) Multiple circuits exceeding 20 relay units (Supply V

0

from MPD-3 type ZVT and V

0

expansion terminals of MDG-A3V relay)

ZCT

“ MZT ” 3

MDG-A3V

①

PCT

ZVT

“ MPD-3 ”

DS

CB

CB CB CB

CB CB CB

ZCT

“ MZT ”

3

MDG-A3V

②

ZCT

“ MZT ”

3

MDG-A3V

③

ZCT

“ MZT ”

3

MDG-A3V

④

ZCT

“ MZT ”

3

MDG-A3V

⑳

ZCT

“ MZT ”

3

MDG-A3V

㉑

ZCT

“ MZT ”

3

MDG-A3V

㉒

※

Encircled numbers in the MDG-A3V relay shown above indicate the number of units installed.

For multiple circuits exceeding 20 relay units, supply V

0

voltage from the V

0

expansion terminals (M-N) of the MDG-A3V relay

(marked by " ※ " in the figures).

The MDG-A3V relay that supplies V

0

voltage from the expansion terminals must receive V

0

voltage directly from the MPD-3 type ZVT.

Each relay directly connected to the ZVT can supply V

0

voltage for 20 relay units.

(Note) To supply V

0

voltage from the expansion terminals, the control power of the supply source relay must be turned on.

The relay that receives V

0

supply from the expansion terminals cannot be operated if the control power of the source relay is not turned on or if it fails. From the viewpoint of system reliability, if up to 20 MDG-A3V relays are installed, it is recommended to connect directly from the MPD-3 type ZVT.

Fig. 2-3 Application examples of MDG-A3V type relay

12 JEP0-IL9554

External connection diagram (Example)

ZCT

“MZT”

K

L

PCT

AC110V kt ℓ t k Z1

P1 P2

MDG-A3V ℓ Z2 a11 a12 a21

Y1 Y2 E a22

(E

D

)

BP

To alarm circuit

AC110V

To P1-P2 of

MDG-A3V

(E

D

)

VT PF

DS

CB

Voltage tripping coil

52a

Pallet switch

BN

N N

MPD-3W

Shield cable

T

MPD-3C

High-voltage capacitor

N

N

MPD-3T

Transformer box

Y1(50Hz)

Y1(60Hz)

Y2

E

(E

A

) (E

D

)

CB

K

ZCT

“MZT”

L

CB CB CB

AC110V

ZCT kt ℓ t k Z1 ℓ Z2

P1 P2

MDG-A3V

Y1 Y2 E

M

N

MDG-

A3V

Same as on the left

Y1 Y2 E

(E

D

)

ZCT

MDG- K

A3V

Same as on the left

ZCT

“MZT”

L

Y1 Y2 E

(E

D

) (E

D

)

CB kt

AC110V

ZCT

“MZT” ℓ t k Z1 ℓ  Z2

P1 P2

MDG-A3V

Y1 Y2 E

M

N

K

L

(E

D

)

(E

D

)

CB

AC110V ZCT kt ℓ t k Z1 ℓ  Z2

P1 P2

MDG-A3V

Y1 Y2 E

M

N

MDG-

A3V

Same as on the left

(E

D

)

Y1 Y2 E

(E

D

)

1. For wiring materials from ZCT, ZVT, and V

0

expansion terminals (M-N), please use 2-core shielded cables with a diameter of

0.75mm

2 or more and connect their shields to D-class grounding. The cable burden shall be less than 5 Ω both ways.

(In the case of 0.75mm

2 , one way is about 100 meters.)

2. The number of MDG-A3V and MVG-A3V relay which can be directly connected from MPD-3 type ZVT is up to 20. However, previous models (e.g. MDG-A1V or MVG-A1V relay) or another series (e.g. MELPRO-D/S series) are combined, the number of connectable relays is limited to 5. Don't exceed the maximum number of relay units.

If many units more than the limitation are needed to apply V

0

voltage, supply V

0

from expansion terminals (M-N) to Y1-Y2 terminals. The MDG-A3V relay that supplies V

0

voltage from the expansion terminals must receive V

0

voltage directly from the

MPD-3 type ZVT. Each relay directly connected to the ZVT can supply V

0

voltage for 20 relay units.

3. To supply V

0

voltage from the expansion terminals, the control power of the supply source relay must be turned on.

The relay that receives V

0

supply from the expansion terminals cannot be operated if the control power of the source relay is not turned on or if it fails. From the viewpoint of system reliability, if up to 20 MDG-A3V relays are installed, it is recommended to connect directly from the MPD-3 type ZVT.

4. The CB tripping circuit and alarm circuit of MDG-A3V relay for feeder protection are omitted in this figure above.

The same circuit as in the power receiving point is required.

5. This figure is shown about the voltage tripping system. For current tripping system, MGX-1 type auxiliary box is required.

6. For MDG-A3V-RD type relay, please connect terminals between Z2 and Y2 with 2mm 2 cable when sub-unit of the relay is drew out.

7. Don't connect the " ℓ " terminal of MZT type ZCT to ground.

● Connect line.

Fig. 2-4 External connection diagram

13 JEP0-IL9554

Operation value settings and using condition settings

1. Operation value settings

In general, the operation value settings are set as follow,

2. Using condition settings

For all using condition setting switches, factory settings but these values should be set with due consideration given to various conditions of the systems, such as residual voltage and current, and protection coordination.

＜ Setting examples ＞

Power receiving point:

I

0

=0.2

～ 0.4A, V

0

=5 ～ 10%, T=0.2

～ 0.3s

Branch feeder:

I

0

=Equivalent or smaller to power receiving point

V

0

=5 ～ 10%, T=Instantaneous (Approx. 70ms)

For details, please consult with an electric power company.

In regard to V

0

setting, set it more than V

0

measured value in order to avoid unwanted operation. are set to a default of OFF.

(1) Frequency (SW1):

50Hz = ON, 60Hz = OFF

(2) Output contact (SW2):

Self-hold = ON, Auto-reset = OFF

(3) Maximum sensitivity angle (SW3):

Lead 10 ° (for reactor grounding system) = ON,

Lead 45 ° (for non-grounding system) = OFF

Precautions for design and installation

＜ Connection ＞

(1) Test terminals of ZCT: The test terminals of ZCT (kt and ℓ t) are used only for the operation test and keep them open after the test. (Do not short the test terminals.)

(2) Wiring material: Since the MDG-A3V relay is a high sensitivity digital type relay, it is necessary to suppress surge and noise from the main circuit and other lines.

Therefore, use 2-core shielded cables with a diameter of 0.75mm

2 or more to connect to the terminals of the relay (Z1, Z2, Y1, Y2, M, N), and connect the shield to E terminal of the relay or Dclass grounding. The cable burden shall be 5 Ω or less for both ways. (In the case of 0.75mm

2 , one way is about 100 meters.)

(3) Secondary wiring of ZCT: The secondary terminal (k, ℓ ), and the test terminal (kt, ℓ t) are double nuts.

The wiring is connected between the nuts. When connecting, do not loosen the inner side (ZCT side) nut.

(4) Polarity: Polarity is very important to this relay.

Please pay attention to polarity for connecting from

ZCT and ZVT, and grounding point is also important.

(5) ZVT position: The position of ZVT does not affect the characteristics or protection, either on the power supply side or the load side of the CB.

(7) Handling of power cable: Please handle with care not to damage the outer sheath of ZCT primary cable.

The bending radius should be more than 10 times the conductor outer diameter. Please locate the threephase cable symmetrically in the ZCT through hole.

(8) Grounding of ZVT: Please connect the "E" terminal of

MPD-3 type ZVT to A-class grounding.

(9) Grounding of MDG-A3V relay: Because the Z2 terminal and Y2 terminal are internally short-circuited, ground only one point of the Y2 terminal of the MPD-

3 type ZVT or the Y2 terminal of the MDG-A3V relay.

When the V

0

expansion terminal is used, ground only

N terminal of the relay.

(10) Connection to ZCT: Only one ZCT can be connected to one MDG-A3V relay. If two or more ZCTs are connected in parallel, correct detection may not be possible.

＜ Caution on withstand voltage test ＞

(1) After the relay is mounted into the panel, when the test is performed between the high-voltage circuit and the earth/the low-voltage circuit, be sure to check that the secondary side of VT and ZCT are grounded and that the relay is disconnected from

ZVT.

(2) When the test is performed between the low-voltage

(6) Shield grounding of power cable: When an electric circuit and the earth, be sure to disconnect the power cable is used at the primary side of ZCT, pay attention to the shield grounding as shown in

JEAC8011 regulations. secondary side of VT, ZVT, and ZCT from the earth.

14 JEP0-IL9554

Handling precautions

1. Panel mounting

① Be sure to connect the "E" terminal of the relay to Dclass grounding.

② The relay of unit-drawer type (RD type) can be drawn out from the case.

2.

Use and operation

① About the setting switches for using condition, factory settings are set to a default of OFF. So it is necessary to set the switches according to the conditions.

② Please refrain from changing the setting value during operation, since unwanted operation may occur. However, if the setting change is unavoidable, please press the

CPU reset button in order to lock the relay function.

Test

③ Don't leave rotary switches with halfway (indefinite) state.

④ The RUN LED lights up in the normal condition when the rated auxiliary power supply is input. If it still turns off when the auxiliary power supply voltage exceeds 85V, please contact our local agent and branch office since the relay may fail.

3.

Connection of V

0

input terminal

① Be sure to connect the V

0

input terminal (Y1-Y2) to the

MPD-3 type ZVT or the MDG relay supplying V

0

when turning on the relay power supply.

A relay test is carried out sufficiently before shipment, but at the following cases, it is recommended the test should be carried out again. a.

When the products are delivered and unpacked b.

At the time of starting operation of equipment c.

At the time of periodic inspection (Usually once a year)

1. At the time of testing

① The input waveform should be a sine wave with little distortion.

② During the test, set the position of the indicator select switch to "V

0

MEASURE", "I

0

MEASURE", "PHASE

MEASURE", or "PICKUP". Set the other setting switches according to the test conditions of the operating characteristic control point.

③ If user-defined control point is specified (e.g. accuracy of relay characteristic is controlled at service conditions), execute the test at the manufacturer-defined characteristic control point before in-service operation and then check accuracy of the relay. After that, execute the test at the userdefined control point, and use this data as a later reference.

④ Perform the test in combination with ZCT (MZT type) and

ZVT (MPD-3 type). Otherwise, direct input to the relay may cause burning out.

2. Withstand voltage test a. Please disconnect the relay from ZCT and ZVT. If a voltage higher than the rated value is applied, it may burn out. b. Apply 2000V AC (commercial frequency) between all circuits and earth (E terminal) for one minute, and make sure that there is no problem.

Voltage applied terminals

Y1 Z1 P1 M a11 a12

Y2 Z2 P2 N a21 a22 a11 a12 a21 a22 a11 a12 a21 a22

M

E c. Apply 2000V AC (commercial frequency) between separate circuits for one minute, and make sure that there is no problem.

Voltage applied terminals

P1 P2

Y1 Y2

Z1 Z2

M N

P1 P2

P1 P2

P1 P2 a11 a12 a21 a22 a11 a12 a21 a22

Y1 Y2

Z1 Z2

N

Note) Never apply a test voltage between these circuits.

Y1 Y2 ～ , ～ ,

Z1 Z2

～

15 JEP0-IL9554

3. Operation characteristics test [MDG+ZCT+ZVT combination]

① In the field test, it is necessary to check the wiring or directionality, so the voltage is applied from the primary side (high-voltage side) of zero-sequence voltage detector. There are 2 ways to do this, either by combining the devices to form a test circuit (refer to Fig. 2-5) or by using a commercially available relay tester shown in Fig.

2-6.

② When this test is carried out, be sure that the main circuit is turned OFF.

③ When the rated power supply voltage is applied, the RUN display LED (green) lights up. This indicates that the relay works properly.

④ By turning the indicator select switch to "TEST" and pushing "TEST" button for 2 seconds or more, output contact can be forced to operate (except for the case of LOCK setting).

4. Operation characteristic control point

Perform the test periodically according to the following test conditions and criteria.

Test item

I

0

setting V

0

setting

Test condition

Time setting Input

I

V

0

0

operation value

operation value

Each setting

Minimum

Minimum

Each setting

Instantaneous

Instantaneous

V

0

= Setting × 150% at the max. sensitivity angle

I

0

= Setting × 150% at the max. sensitivity angle

Criteria

± 10% of setting value

± 25% of setting value

Phase characteristics

Operating time characteristics

Minimum

Minimum

Minimum

Minimum

Instantaneous

Instantaneous

0.2s

0.3s or more

V

0

= Setting × 150%

I

0

= Setting × 1000%

V

0

= Setting × 150%

I

0

= Setting × 130%

Applied at the same time at the max. sensitivity angle

Max. sensitivity angle = 45 ° setting

Lag: 25 ～ 65 °

Lead: 115 ～ 155 °

Max. sensitivity angle = 10 ° setting

Lag: 50 ～ 85 °

Lead: 90 ～ 130 °

50 ～ 100ms

0.1

～ 0.3s

± 20% of setting time

16 JEP0-IL9554

DS

K

ZCT

“

MZT

”

L kt k ℓ ℓ t

Make sure that this circuit is open before test.

※

※

MDG-A3V

Z1

Z2 a11 a12

E

Y1 Y2

(E D )

P1

P2

AC100/110V

CB

Tripping coil

AC100V or

DC100V

52a

U V W

From ②

From

①

Phase meter

－

φ

＋

SW

20 Ω

0~1000 Ω

A

R 1 R 2

U u

AC100/110V

P1 P2

Voltage regulator

V

P1, P2 terminal of MDG relay v

DS K

ZCT

“MZT”

Black clip

Red clip kt

L ℓ t

※ ※

MPD-3C

MPD-3W

MPD-3T

T

N

E

Y1

Y2

V

0~1000V

(E

A

)

※

(E

D

)

※

To

①

To ②

Fig. 2-5 Test method using combinations of the devices

CB

Remove the fuses

P1

VT

P2

(E

D

)

Remove P1 and P2

※ ※

MPD-3C

MPD-3W

Red clip

Notes)

These figures show that the V

0 voltage is applied from the primary side (high-voltage side) of MPD-3C capacitor simultaneously in three-phase.

If the V

0

voltage is applied from the test terminal (T) of MPD-3T, the voltage value should be onetenth of the value from MPD-3C high-voltage side.

Do not apply voltage into test terminal (T) more than 380V.

● If there is no test terminal (kt, ℓ t) of ZCT, please pass the red clip of current cord through ZCT through hole and connect with the black clip.

● For MDG-A3V relay, the ○ side of input polarity is that:

Z1 with I

0

input

Y2 with V

0

input

● Don't forget to remove the wires marked by " ※ " in the figures after the test.

● If the V

0

voltage is applied from the test terminal (T) of MPD-3T, the wires marked by " ※ " in the figures are not required.

● Perform the test in combination with ZCT (MZT type) and ZVT (MPD-

3 type). Otherwise, direct input to the relay may cause burning out.

a21

MDG-A3V a22

MPD-3T

Y1 N

T

Y2

E

Z2 Z1 P1 P2 Y2 Y1 a11 a12 E

(E

D

)

Current cord

Red clip

Black clip

Auxiliary power supply cord

Tripping cord

(E

D

)

(E A )

Black clip

Voltage cord

AC100/110V

V A φ

Fig. 2-6 Test method using relay tester

17 JEP0-IL9554

Terminal layout

P1 M Y1 Z1 × a11 a12

P2

9

N

9

Y2

9

Z2

9

E

9 a21 a22

9

14

MDG-A3V-R/RD

Do not connect to the " × " terminals, or the relay may not operate properly.

Fig. 2-7 Terminal layout

Drawing out and housing operation of subunit (Unit-drawer type)

For unit-drawer type (RD type), it is possible to draw Before the subunit is to be drawn out, ensure that the out the subunit from the case without removing external wiring, which makes easier to carry out inspection and testing.

When drawing out and housing, be careful not to touch the electrical circuit (e.g. substrate, capacitor, and transformer) and be sure to hold the drawer handle or the frame part when transporting. (Touching the electrical circuit may cause electric shock or damage to the circuit.) following items are checked in order not to carry out the work in hot-line condition.

・ Lock of the tripping circuit

・ Turning off the main circuit

・ Disconnect CT/VT circuit

・ Turning off the auxiliary power supply

The CT circuit is equipped with an automatic short circuit piece so that the CT secondary circuit won't be opened even if the relay subunit is drawn out without disconnecting the CT circuit.

Subunit

Connector of case

Cover (Transparent)

Connector of subunit

(Back side)

Drawer handle

(Back side)

Drawer fixing screw

Fig. 2-8 Structures of unit-drawer type (RD type)

18 JEP0-IL9554

1. Procedure of drawing out

Cover

Drawer fixing screw

① Open the cover and remove the drawer fixing screw.

② Close the cover and pull out the subunit with your finger hooked on the drawer handle on both sides.

③ Support the frame of subunit and pull out.

2. Procedure of housing

Cover

① Support the frame of subunit and place the subunit in the case along the rails.

Drawer fixing screw

② Insert the subunit into the case horizontally.

③ Open the cover and tighten the drawer fixing screw.

19 JEP0-IL9554

Handling of the cover

1. Opening and closing

Please open the cover by placing your fingertip on the convex part in the right side of the cover as shown in Fig. 2-9.

Fig. 2-9

2. How to replace the cover

･ Removing the cover

Open the cover, and lightly push up the upper side of the cover from the inner surface.

Then, remove from the protrusion of the body.

Enlarged view of the upper side

･ Installing the cover

As shown in Fig. 2-10, mount the holes on the upper side of the cover to the protrusion of the body.

Then, press down lightly on the lower side of the cover

Cover and mount to the protrusion of the body in the same way as above.

Fig. 2-10

・ When replacing the cover during operation, be careful not to touch the switches.

Body

20 JEP0-IL9554

External dimensions and Panel cut-out

152 3

32

136

104

13

124

φ 140 ～φ 142

2-M6 screw

14-M3.5 screw

Minimum pitch

180

2φ 7 hole

Fig. 2-11 MDG-A3V-R (Unit: mm)

Same as the center of panel cut-out

152 3

32

136

104

36

11

124

φ 140 ～φ 142

2-M6 screw

14-M3.5 screw

Minimum pitch

182

2φ 7 hole

Fig. 2-12 MDG-A3V-RD (Unit: mm)

Improvement on the reliability of protection function

Any parts and materials applied to the protection relay have limited lifetime which will bring the degradation to the relay. The degree of degradation will be variable depending on the purpose, aging, usage environment, and unevenness on the performance of each part.

Our company designs its products so that the recommended renewal period is 15 years or more.

However, there may be some possibilities to occur any failures before reaching 15 years due to above reasons.

To prevent unwanted operation or no operation of relay, it is recommended to apply the relay with self-diagnosis function and/or multiplexing relay system such as dual or duplex scheme.

21 JEP0-IL9554

HEAD OFFICE ： 7-3 MARUNOUCHI 2-CHOME, CHIYODA-KU TOKYO, 100-8310, JAPAN

First edition: Jan. 2021