Exhibit 3(a)

Composite Of Amended

and

Restated Certificate of Incorporation

of

AEP Texas Inc.

Under the General Corporation Law of the State of Delaware

As filed with the Secretary of State

of Delaware on July 31, 1925

and

amended as filed on

May 2, 1974, April 25, 1990, May 29, 1991,

June 22, 2000, January 21, 2003 and December 22, 2016

COMPOSITE OF AMENDED AND

RESTATED CERTIFICATE OF INCORPORATION

Under the Delaware General Corporation Law

of

AEP TEXAS INC.

FIRST: The name of the Corporation is AEP Texas Inc.

SECOND: The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the Delaware General Corporation Law.

THIRD: The name of the Corporation’s initial agent for service of process in the State of Delaware is:

The Corporation Trust Company

Corporation Trust Center

1209 Orange Street

Wilmington, DE 19801

County of New Castle

FOURTH: The total number of shares of capital stock which the Corporation shall have authority to issue is 100, of which all shares shall be shares of Common Stock, with $.01 par value.

Except as otherwise provided by law, the Common Stock shall have the exclusive right to vote for the election of directors and for all other purposes. Each share of Common Stock shall have one vote, and the Common Stock shall vote together as a single class.

FIFTH: Unless and except to the extent that the Bylaws of the Corporation shall so require, the election of directors of the Corporation need not be by written ballot.

SIXTH: In furtherance and not in limitation of the powers conferred by law, the Board of Directors of the Corporation (the “Board”) is expressly authorized and empowered to make, alter and repeal the Bylaws of the Corporation by a majority vote at any regular or special meeting of the Board or by written consent, subject to the power of the stockholders of the Corporation to alter or repeal any Bylaws made by the Board.

SEVENTH: The Corporation reserves the right at any time from time to time to amend, alter, change or repeal any provision contained in this Certificate of Incorporation, and any other provisions authorized by the laws of the State of Delaware at the time in force may be added or inserted, in the manner now or hereafter prescribed by law; and all rights, preferences and privileges of whatsoever nature conferred upon stockholders, directors or

any other persons whomsoever by and pursuant to this Certificate of Incorporation in its present form or as hereafter amended are granted subject to the right reserved in this Article.

EIGHTH: A director of the Corporation shall not be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director’s duty of loyalty to the Corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) under Section 174 of the Delaware General Corporation Law, or (iv) for any transaction from which the director derived an improper personal benefit.

NINTH: Each person who was or is made a party or is threatened to be made a party to or is involved (including, without limitation, as a witness) in any threatened, pending or completed action, suit, arbitration, alternative dispute resolution mechanism, investigation, administrative hearing or any other proceeding, whether civil, criminal, administrative or investigative (“Proceeding”), by reason of the fact that such person (the “Indemnitee”) is or was a director or officer of the Corporation or is or was serving at the request of the Corporation as a director or officer of another corporation or of a partnership, joint venture, trust or other enterprise, including service with respect to an employee benefit plan, whether the basis of such Proceeding is alleged action in an official capacity as a director or officer or in any other capacity while serving as such a director or officer, shall be indemnified and held harmless by the Corporation to the full extent permitted by law, as the same exists or may hereafter be amended (but, in the case of any such amendment, only to the extent such amendment permits the Corporation to provide broader indemnification rights than said law permitted the Corporation to provide prior to such amendment), or by other applicable law as then in effect, against all expense, liability, losses and claims (including attorneys’ fees, judgements, fines, excise taxes under the Employee Retirement Income Security Act of 1974, as amended from time to time, penalties and amounts to be paid in settlement) actually incurred or suffered by such Indemnitee in connection with such Proceeding.

TENTH: The Corporation may maintain insurance, at its expense, to protect itself and any director, officer, employee or agent of the Corporation or another corporation, partnership, joint venture, trust or other enterprise against any expense, liability or loss, whether or not the Corporation would have the power to indemnify such person against such expense, liability or loss under the Delaware General Corporation Law.